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| -rw-r--r-- | README.markdown | 2 | ||||
| -rw-r--r-- | c++.html.markdown | 2 | ||||
| -rw-r--r-- | c.html.markdown | 54 | ||||
| -rw-r--r-- | coldfusion.html.markdown | 321 | ||||
| -rw-r--r-- | cs-cz/python3.html.markdown | 6 | ||||
| -rw-r--r-- | csharp.html.markdown | 55 | ||||
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| -rw-r--r-- | fr-fr/objective-c-fr.html.markdown | 2 | ||||
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| -rw-r--r-- | go.html.markdown | 2 | ||||
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| -rw-r--r-- | ru-ru/php-ru.html.markdown | 61 | ||||
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27 files changed, 1652 insertions, 318 deletions
diff --git a/README.markdown b/README.markdown index 774797d5..28fa5093 100644 --- a/README.markdown +++ b/README.markdown @@ -8,7 +8,7 @@ commented code and explained as they go. ... to write more inline code tutorials. Just grab an existing file from this repo and copy the formatting (don't worry, it's all very simple). -Make a new file, send a pull request, and if it passes muster I'll get it up pronto. +Make a new file, send a pull request, and if it passes master I'll get it up pronto. Remember to fill in the "contributors" fields so you get credited properly! diff --git a/c++.html.markdown b/c++.html.markdown index 6f4d0562..2bee51dc 100644 --- a/c++.html.markdown +++ b/c++.html.markdown @@ -404,6 +404,8 @@ int main() { // Inheritance: // This class inherits everything public and protected from the Dog class +// as well as private but may not directly access private members/methods +// without a public or protected method for doing so class OwnedDog : public Dog { void setOwner(const std::string& dogsOwner); diff --git a/c.html.markdown b/c.html.markdown index aaf176c1..fb77ca50 100644 --- a/c.html.markdown +++ b/c.html.markdown @@ -6,6 +6,7 @@ contributors: - ["Árpád Goretity", "http://twitter.com/H2CO3_iOS"] - ["Jakub Trzebiatowski", "http://cbs.stgn.pl"] - ["Marco Scannadinari", "https://marcoms.github.io"] + - ["himanshu", "https://github.com/himanshu81494"] --- @@ -27,6 +28,7 @@ Multi-line comments don't nest /* Be careful */ // comment ends on this line... */ // ...not this one! // Constants: #define <keyword> +// Constants are written in all-caps out of convention, not requirement #define DAYS_IN_YEAR 365 // Enumeration constants are also ways to declare constants. @@ -56,6 +58,15 @@ int add_two_ints(int x1, int x2); // function prototype // Your program's entry point is a function called // main with an integer return type. int main(void) { + // your program +} + +// The command line arguments used to run your program are also passed to main +// argc being the number of arguments - your program's name counts as 1 +// argv is an array of character arrays - containing the arguments themselves +// argv[0] = name of your program, argv[1] = first argument, etc. +int main (int argc, char** argv) +{ // print output using printf, for "print formatted" // %d is an integer, \n is a newline printf("%d\n", 0); // => Prints 0 @@ -308,7 +319,29 @@ int main(void) { exit(-1); break; } - + /* + using "goto" in C + */ + typedef enum { false, true } bool; + // for C don't have bool as data type :( + bool disaster = false; + int i, j; + for(i=0;i<100;++i) + for(j=0;j<100;++j) + { + if((i + j) >= 150) + disaster = true; + if(disaster) + goto error; + } + error : + printf("Error occured at i = %d & j = %d.\n", i, j); + /* + https://ideone.com/GuPhd6 + this will print out "Error occured at i = 52 & j = 99." + */ + + /////////////////////////////////////// // Typecasting /////////////////////////////////////// @@ -474,7 +507,24 @@ char c[] = "This is a test."; str_reverse(c); printf("%s\n", c); // => ".tset a si sihT" */ - +/* +as we can return only one variable +to change values of more than one variables we use call by reference +*/ +void swapTwoNumbers(int *a, int *b) +{ + int temp = *a; + *a = *b; + *b = temp; +} +/* +int first = 10; +int second = 20; +printf("first: %d\nsecond: %d\n", first, second); +swapTwoNumbers(&first, &second); +printf("first: %d\nsecond: %d\n", first, second); +// values will be swapped +*/ // if referring to external variables outside function, must use extern keyword. int i = 0; void testFunc() { diff --git a/coldfusion.html.markdown b/coldfusion.html.markdown new file mode 100644 index 00000000..e2f0737d --- /dev/null +++ b/coldfusion.html.markdown @@ -0,0 +1,321 @@ +--- +language: ColdFusion +contributors: + - ["Wayne Boka", "http://wboka.github.io"] +filename: LearnColdFusion.cfm +--- + +ColdFusion is a scripting language for web development. +[Read more here.](http://www.adobe.com/products/coldfusion-family.html) + +```ColdFusion + +<em>HTML tags have been provided for output readability</em> + +<!--- Comments start with "<!---" and end with "--->" ---> +<!--- + Comments can + also + span + multiple lines +---> + +<!--- CFML tags have a similar format to HTML tags. ---> +<h1>Simple Variables</h1> +<!--- Variable Declaration: Variables are loosely typed, similar to javascript ---> +<p>Set <b>myVariable</b> to "myValue"</p> +<cfset myVariable = "myValue" /> +<p>Set <b>myNumber</b> to 3.14</p> +<cfset myNumber = 3.14 /> + +<!--- Displaying simple data ---> +<!--- Use <cfoutput> for simple values such as strings, numbers, and expressions ---> +<p>Display <b>myVariable</b>: <cfoutput>#myVariable#</cfoutput></p><!--- myValue ---> +<p>Display <b>myNumber</b>: <cfoutput>#myNumber#</cfoutput></p><!--- 3.14 ---> + +<hr /> + +<h1>Complex Variables</h1> +<!--- Declaring complex variables ---> +<!--- Declaring an array of 1 dimension: literal or bracket notation ---> +<p>Set <b>myArray1</b> to an array of 1 dimension using literal or bracket notation</p> +<cfset myArray1 = [] /> +<!--- Declaring an array of 1 dimension: function notation ---> +<p>Set <b>myArray2</b> to an array of 1 dimension using function notation</p> +<cfset myArray2 = ArrayNew(1) /> + +<!--- Outputting complex variables ---> +<p>Contents of <b>myArray1</b></p> +<cfdump var="#myArray1#" /> <!--- An empty array object ---> +<p>Contents of <b>myArray2</b></p> +<cfdump var="#myArray2#" /> <!--- An empty array object ---> + +<!--- Operators ---> +<!--- Arithmetic ---> +<h1>Operators</h1> +<h2>Arithmetic</h2> +<p>1 + 1 = <cfoutput>#1 + 1#</cfoutput></p> +<p>10 - 7 = <cfoutput>#10 - 7#<br /></cfoutput></p> +<p>15 * 10 = <cfoutput>#15 * 10#<br /></cfoutput></p> +<p>100 / 5 = <cfoutput>#100 / 5#<br /></cfoutput></p> +<p>120 % 5 = <cfoutput>#120 % 5#<br /></cfoutput></p> +<p>120 mod 5 = <cfoutput>#120 mod 5#<br /></cfoutput></p> + +<hr /> + +<!--- Comparison ---> +<h2>Comparison</h2> +<h3>Standard Notation</h3> +<p>Is 1 eq 1? <cfoutput>#1 eq 1#</cfoutput></p> +<p>Is 15 neq 1? <cfoutput>#15 neq 1#</cfoutput></p> +<p>Is 10 gt 8? <cfoutput>#10 gt 8#</cfoutput></p> +<p>Is 1 lt 2? <cfoutput>#1 lt 2#</cfoutput></p> +<p>Is 10 gte 5? <cfoutput>#10 gte 5#</cfoutput></p> +<p>Is 1 lte 5? <cfoutput>#1 lte 5#</cfoutput></p> + +<h3>Alternative Notation</h3> +<p>Is 1 == 1? <cfoutput>#1 eq 1#</cfoutput></p> +<p>Is 15 != 1? <cfoutput>#15 neq 1#</cfoutput></p> +<p>Is 10 > 8? <cfoutput>#10 gt 8#</cfoutput></p> +<p>Is 1 < 2? <cfoutput>#1 lt 2#</cfoutput></p> +<p>Is 10 >= 5? <cfoutput>#10 gte 5#</cfoutput></p> +<p>Is 1 <= 5? <cfoutput>#1 lte 5#</cfoutput></p> + +<hr /> + +<!--- Control Structures ---> +<h1>Control Structures</h1> + +<cfset myCondition = "Test" /> + +<p>Condition to test for: "<cfoutput>#myCondition#</cfoutput>"</p> + +<cfif myCondition eq "Test"> + <cfoutput>#myCondition#. We're testing.</cfoutput> +<cfelseif myCondition eq "Production"> + <cfoutput>#myCondition#. Proceed Carefully!!!</cfoutput> +<cfelse> + myCondition is unknown +</cfif> + +<hr /> + +<!--- Loops ---> +<h1>Loops</h1> +<h2>For Loop</h2> +<cfloop from="0" to="10" index="i"> + <p>Index equals <cfoutput>#i#</cfoutput></p> +</cfloop> + +<h2>For Each Loop (Complex Variables)</h2> + +<p>Set <b>myArray3</b> to [5, 15, 99, 45, 100]</p> + +<cfset myArray3 = [5, 15, 99, 45, 100] /> + +<cfloop array="#myArray3#" index="i"> + <p>Index equals <cfoutput>#i#</cfoutput></p> +</cfloop> + +<p>Set <b>myArray4</b> to ["Alpha", "Bravo", "Charlie", "Delta", "Echo"]</p> + +<cfset myArray4 = ["Alpha", "Bravo", "Charlie", "Delta", "Echo"] /> + +<cfloop array="#myArray4#" index="s"> + <p>Index equals <cfoutput>#s#</cfoutput></p> +</cfloop> + +<h2>Switch Statement</h2> + +<p>Set <b>myArray5</b> to [5, 15, 99, 45, 100]</p> + +<cfset myArray5 = [5, 15, 99, 45, 100] /> + +<cfloop array="#myArray5#" index="i"> + <cfswitch expression="#i#"> + <cfcase value="5,15,45" delimiters=","> + <p><cfoutput>#i#</cfoutput> is a multiple of 5.</p> + </cfcase> + <cfcase value="99"> + <p><cfoutput>#i#</cfoutput> is ninety-nine.</p> + </cfcase> + <cfdefaultcase> + <p><cfoutput>#i#</cfoutput> is not 5, 15, 45, or 99.</p> + </cfdefaultcase> + </cfswitch> +</cfloop> + +<hr /> + +<h1>Converting types</h1> + +<style> + table.table th, table.table td { + border: 1px solid #000000; + padding: 2px; + } + + table.table th { + background-color: #CCCCCC; + } +</style> + +<table class="table" cellspacing="0"> + <thead> + <tr> + <th>Value</th> + <th>As Boolean</th> + <th>As number</th> + <th>As date-time</th> + <th>As string</th> + </tr> + </thead> + <tbody> + <tr> + <th>"Yes"</th> + <td>TRUE</td> + <td>1</td> + <td>Error</td> + <td>"Yes"</td> + </tr> + <tr> + <th>"No"</th> + <td>FALSE</td> + <td>0</td> + <td>Error</td> + <td>"No"</td> + </tr> + <tr> + <th>TRUE</th> + <td>TRUE</td> + <td>1</td> + <td>Error</td> + <td>"Yes"</td> + </tr> + <tr> + <th>FALSE</th> + <td>FALSE</td> + <td>0</td> + <td>Error</td> + <td>"No"</td> + </tr> + <tr> + <th>Number</th> + <td>True if Number is not 0; False otherwise.</td> + <td>Number</td> + <td>See "Date-time values" earlier in this chapter.</td> + <td>String representation of the number (for example, "8").</td> + </tr> + <tr> + <th>String</th> + <td>If "Yes", True <br>If "No", False <br>If it can be converted to 0, False <br>If it can be converted to any other number, True</td> + <td>If it represents a number (for example, "1,000" or "12.36E-12"), it is converted to the corresponding number.</td> + <td>If it represents a date-time (see next column), it is converted to the numeric value of the corresponding date-time object. <br>If it is an ODBC date, time, or timestamp (for example "{ts '2001-06-14 11:30:13'}", or if it is expressed in a standard U.S. date or time format, including the use of full or abbreviated month names, it is converted to the corresponding date-time value. <br>Days of the week or unusual punctuation result in an error. <br>Dashes, forward-slashes, and spaces are generally allowed.</td> + <td>String</td> + </tr> + <tr> + <th>Date</th> + <td>Error</td> + <td>The numeric value of the date-time object.</td> + <td>Date</td> + <td>An ODBC timestamp.</td> + </tr> + </tbody> +</table> + +<hr /> + +<h1>Components</h1> + +<em>Code for reference (Functions must return something to support IE)</em> + +<pre> +<cfcomponent> + <cfset this.hello = "Hello" /> + <cfset this.world = "world" /> + + <cffunction name="sayHello"> + <cfreturn this.hello & ", " & this.world & "!" /> + </cffunction> + + <cffunction name="setHello"> + <cfargument name="newHello" type="string" required="true" /> + + <cfset this.hello = arguments.newHello /> + + <cfreturn true /> + </cffunction> + + <cffunction name="setWorld"> + <cfargument name="newWorld" type="string" required="true" /> + + <cfset this.world = arguments.newWorld /> + + <cfreturn true /> + </cffunction> + + <cffunction name="getHello"> + <cfreturn this.hello /> + </cffunction> + + <cffunction name="getWorld"> + <cfreturn this.world /> + </cffunction> +</cfcomponent> +</pre> + +<cfset this.hello = "Hello" /> +<cfset this.world = "world" /> + +<cffunction name="sayHello"> + <cfreturn this.hello & ", " & this.world & "!" /> +</cffunction> + +<cffunction name="setHello"> + <cfargument name="newHello" type="string" required="true" /> + + <cfset this.hello = arguments.newHello /> + + <cfreturn true /> +</cffunction> + +<cffunction name="setWorld"> + <cfargument name="newWorld" type="string" required="true" /> + + <cfset this.world = arguments.newWorld /> + + <cfreturn true /> +</cffunction> + +<cffunction name="getHello"> + <cfreturn this.hello /> +</cffunction> + +<cffunction name="getWorld"> + <cfreturn this.world /> +</cffunction> + + +<b>sayHello()</b> +<cfoutput><p>#sayHello()#</p></cfoutput> +<b>getHello()</b> +<cfoutput><p>#getHello()#</p></cfoutput> +<b>getWorld()</b> +<cfoutput><p>#getWorld()#</p></cfoutput> +<b>setHello("Hola")</b> +<cfoutput><p>#setHello("Hola")#</p></cfoutput> +<b>setWorld("mundo")</b> +<cfoutput><p>#setWorld("mundo")#</p></cfoutput> +<b>sayHello()</b> +<cfoutput><p>#sayHello()#</p></cfoutput> +<b>getHello()</b> +<cfoutput><p>#getHello()#</p></cfoutput> +<b>getWorld()</b> +<cfoutput><p>#getWorld()#</p></cfoutput> +``` + +## Further Reading + +The links provided here below are just to get an understanding of the topic, feel free to Google and find specific examples. + +1. [Coldfusion Reference From Adobe](https://helpx.adobe.com/coldfusion/cfml-reference/topics.html) diff --git a/cs-cz/python3.html.markdown b/cs-cz/python3.html.markdown index 11c8a654..6d2fd1eb 100644 --- a/cs-cz/python3.html.markdown +++ b/cs-cz/python3.html.markdown @@ -48,7 +48,7 @@ Poznámka: Tento článek je zaměřen na Python 3. Zde se můžete [naučit sta -5 // 3 # => -2 -5.0 // 3.0 # => -2.0 -# Pokud použiteje desetinné číslo, výsledek je jím také +# Pokud použijete desetinné číslo, výsledek je jím také 3 * 2.0 # => 6.0 # Modulo @@ -420,7 +420,7 @@ next(iterator) # Vyhodí StopIteration ## 4. Funkce #################################################### -# Pro vytvoření nové funkce použijte def +# Pro vytvoření nové funkce použijte klíčové slovo def def secist(x, y): print("x je {} a y je {}".format(x, y)) return x + y # Hodnoty se vrací pomocí return @@ -520,7 +520,7 @@ class Clovek(object): # podtržítka na začátku a na konci značí, že se jedná o atribut nebo # objekt využívaný Pythonem ke speciálním účelům, ale můžete sami # definovat jeho chování. Metody jako __init__, __str__, __repr__ - # a další se nazývají "magické metody". Nikdy nepoužívejte toto + # a další se nazývají "magické metody". Nikdy nepoužívejte toto # speciální pojmenování pro běžné metody. def __init__(self, jmeno): # Přiřazení parametru do atributu instance jmeno diff --git a/csharp.html.markdown b/csharp.html.markdown index 02650038..7aca2c6f 100644 --- a/csharp.html.markdown +++ b/csharp.html.markdown @@ -6,6 +6,7 @@ contributors: - ["Melvyn Laïly", "http://x2a.yt"] - ["Shaun McCarthy", "http://www.shaunmccarthy.com"] - ["Wouter Van Schandevijl", "http://github.com/laoujin"] + - ["Jo Pearce", "http://github.com/jdpearce"] filename: LearnCSharp.cs --- @@ -159,7 +160,7 @@ on a new line! ""Wow!"", the masses cried"; // List<datatype> <var name> = new List<datatype>(); List<int> intList = new List<int>(); List<string> stringList = new List<string>(); - List<int> z = new List<int> { 9000, 1000, 1337 }; // intialize + List<int> z = new List<int> { 9000, 1000, 1337 }; // initialize // The <> are for generics - Check out the cool stuff section // Lists don't default to a value; @@ -418,12 +419,48 @@ on a new line! ""Wow!"", the masses cried"; // Item is an int Console.WriteLine(item.ToString()); } + + // YIELD + // Usage of the "yield" keyword indicates that the method it appears in is an Iterator + // (this means you can use it in a foreach loop) + public static IEnumerable<int> YieldCounter(int limit = 10) + { + for (var i = 0; i < limit; i++) + yield return i; + } + + // which you would call like this : + public static void PrintYieldCounterToConsole() + { + foreach (var counter in YieldCounter()) + Console.WriteLine(counter); + } + + // you can use more than one "yield return" in a method + public static IEnumerable<int> ManyYieldCounter() + { + yield return 0; + yield return 1; + yield return 2; + yield return 3; + } + + // you can also use "yield break" to stop the Iterator + // this method would only return half of the values from 0 to limit. + public static IEnumerable<int> YieldCounterWithBreak(int limit = 10) + { + for (var i = 0; i < limit; i++) + { + if (i > limit/2) yield break; + yield return i; + } + } public static void OtherInterestingFeatures() { // OPTIONAL PARAMETERS MethodSignatures(3, 1, 3, "Some", "Extra", "Strings"); - MethodSignatures(3, another: 3); // explicity set a parameter, skipping optional ones + MethodSignatures(3, another: 3); // explicitly set a parameter, skipping optional ones // BY REF AND OUT PARAMETERS int maxCount = 0, count; // ref params must have value @@ -443,6 +480,9 @@ on a new line! ""Wow!"", the masses cried"; // ?? is syntactic sugar for specifying default value (coalesce) // in case variable is null int notNullable = nullable ?? 0; // 0 + + // ?. is an operator for null-propagation - a shorthand way of checking for null + nullable?.Print(); // Use the Print() extension method if nullable isn't null // IMPLICITLY TYPED VARIABLES - you can let the compiler work out what the type is: var magic = "magic is a string, at compile time, so you still get type safety"; @@ -610,7 +650,7 @@ on a new line! ""Wow!"", the masses cried"; { return _cadence; } - set // set - define a method to set a proprety + set // set - define a method to set a property { _cadence = value; // Value is the value passed in to the setter } @@ -750,7 +790,7 @@ on a new line! ""Wow!"", the masses cried"; // It's also possible to define custom Indexers on objects. // All though this is not entirely useful in this example, you - // could do bicycle[0] which yields "chris" to get the first passenger or + // could do bicycle[0] which returns "chris" to get the first passenger or // bicycle[1] = "lisa" to set the passenger. (of this apparent quattrocycle) private string[] passengers = { "chris", "phil", "darren", "regina" }; @@ -761,7 +801,7 @@ on a new line! ""Wow!"", the masses cried"; } set { - return passengers[i] = value; + passengers[i] = value; } } @@ -837,7 +877,8 @@ on a new line! ""Wow!"", the masses cried"; bool Broken { get; } // interfaces can contain properties as well as methods & events } - // Class can inherit only one other class, but can implement any amount of interfaces + // Class can inherit only one other class, but can implement any amount of interfaces, however + // the base class name must be the first in the list and all interfaces follow class MountainBike : Bicycle, IJumpable, IBreakable { int damage = 0; @@ -876,7 +917,7 @@ on a new line! ""Wow!"", the masses cried"; ## Topics Not Covered * Attributes - * async/await, yield, pragma directives + * async/await, pragma directives * Web Development * ASP.NET MVC & WebApi (new) * ASP.NET Web Forms (old) diff --git a/css.html.markdown b/css.html.markdown index 811767e6..d8f30ca3 100644 --- a/css.html.markdown +++ b/css.html.markdown @@ -5,25 +5,20 @@ contributors: - ["Marco Scannadinari", "https://github.com/marcoms"] - ["Geoffrey Liu", "https://github.com/g-liu"] - ["Connor Shea", "https://github.com/connorshea"] + - ["Deepanshu Utkarsh", "https://github.com/duci9y"] filename: learncss.css --- -In the early days of the web there were no visual elements, just pure text. But with the -further development of browsers, fully visual web pages also became common. -CSS is the standard language that exists to keep the separation between -the content (HTML) and the look-and-feel of web pages. +In the early days of the web there were no visual elements, just pure text. But with further development of web browsers, fully visual web pages also became common. -In short, what CSS does is to provide a syntax that enables you to target -different elements on an HTML page and assign different visual properties to them. +CSS helps maintain separation between the content (HTML) and the look-and-feel of a web page. -Like any other languages, CSS has many versions. Here we focus on CSS2.0, -which is not the most recent version, but is the most widely supported and compatible version. +CSS lets you target different elements on an HTML page and assign different visual properties to them. -**NOTE:** Because the outcome of CSS consists of visual effects, in order to -learn it, you need try everything in a -CSS playground like [dabblet](http://dabblet.com/). -The main focus of this article is on the syntax and some general tips. +This guide has been written for CSS 2, though CSS 3 is fast becoming popular. +**NOTE:** Because CSS produces visual results, in order to learn it, you need try everything in a CSS playground like [dabblet](http://dabblet.com/). +The main focus of this article is on the syntax and some general tips. ```css /* comments appear inside slash-asterisk, just like this line! @@ -33,219 +28,226 @@ The main focus of this article is on the syntax and some general tips. ## SELECTORS #################### */ -/* Generally, the primary statement in CSS is very simple */ +/* the selector is used to target an element on a page. selector { property: value; /* more properties...*/ } -/* the selector is used to target an element on page. - -You can target all elements on the page using asterisk! */ -* { color:red; } - /* -Given an element like this on the page: +Here is an example element: -<div class='some-class class2' id='someId' attr='value' otherAttr='en-us foo bar' /> +<div class='class1 class2' id='anID' attr='value' otherAttr='en-us foo bar' /> */ -/* you can target it by its name */ -.some-class { } +/* You can target it using one of its CSS classes */ +.class1 { } -/* or by both classes! */ -.some-class.class2 { } +/* or both classes! */ +.class1.class2 { } -/* or by its element name */ +/* or its name */ div { } /* or its id */ -#someId { } +#anID { } -/* or by the fact that it has an attribute! */ +/* or using the fact that it has an attribute! */ [attr] { font-size:smaller; } /* or that the attribute has a specific value */ [attr='value'] { font-size:smaller; } -/* start with a value (CSS3) */ +/* starts with a value (CSS 3) */ [attr^='val'] { font-size:smaller; } -/* or ends with (CSS3) */ +/* or ends with a value (CSS 3) */ [attr$='ue'] { font-size:smaller; } -/* or select by one of the values from the whitespace separated list (CSS3) */ -[otherAttr~='foo'] { font-size:smaller; } +/* or contains a value in a space-separated list */ +[otherAttr~='foo'] { } +[otherAttr~='bar'] { } -/* or value can be exactly “value” or can begin with “value” immediately followed by “-” (U+002D) */ +/* or contains a value in a dash-separated list, ie, "-" (U+002D) */ [otherAttr|='en'] { font-size:smaller; } -/* and more importantly you can combine these together -- there shouldn't be -any space between different parts because that makes it to have another -meaning. */ +/* You can concatenate different selectors to create a narrower selector. Don't + put spaces between them. */ div.some-class[attr$='ue'] { } -/* you can also select an element based on its parent. */ +/* You can select an element which is a child of another element */ +div.some-parent > .class-name { } + +/* or a descendant of another element. Children are the direct descendants of + their parent element, only one level down the tree. Descendants can be any + level down the tree. */ +div.some-parent .class-name { } + +/* Warning: the same selector without a space has another meaning. + Can you guess what? */ +div.some-parent.class-name { } -/* an element which is direct child of an element (selected the same way) */ -div.some-parent > .class-name {} +/* You may also select an element based on its adjacent sibling */ +.i-am-just-before + .this-element { } -/* or any of its parents in the tree - the following basically means any element that has class "class-name" - and is child of a div with class name "some-parent" IN ANY DEPTH */ -div.some-parent .class-name {} +/* or any sibling preceding it */ +.i-am-any-element-before ~ .this-element { } -/* warning: the same selector without space has another meaning. - can you say what? */ -div.some-parent.class-name {} +/* There are some selectors called pseudo classes that can be used to select an + element when it is in a particular state */ -/* you also might choose to select an element based on its direct - previous sibling */ -.i-am-before + .this-element { } +/* for example, when the cursor hovers over an element */ +selector:hover { } -/* or any sibling before this */ -.i-am-any-before ~ .this-element {} +/* or a link has been visited */ +selector:visited { } -/* There are some pseudo classes that allows you to select an element - based on its page behaviour (rather than page structure) */ +/* or hasn't been visited */ +selected:link { } -/* for example for when an element is hovered */ -selector:hover {} +/* or an element in focus */ +selected:focus { } -/* or a visited link */ -selected:visited {} +/* any element that is the first child of its parent */ +selector:first-child {} -/* or not visited link */ -selected:link {} +/* any element that is the last child of its parent */ +selector:last-child {} -/* or an input element which is focused */ -selected:focus {} +/* Just like pseudo classes, pseudo elements allow you to style certain parts of a document */ +/* matches a virtual first child of the selected element */ +selector::before {} + +/* matches a virtual last child of the selected element */ +selector::after {} + +/* At appropriate places, an asterisk may be used as a wildcard to select every + element */ +* { } /* all elements */ +.parent * { } /* all descendants */ +.parent > * { } /* all children */ /* #################### ## PROPERTIES #################### */ selector { - - /* Units */ - width: 50%; /* in percent */ - font-size: 2em; /* times current font-size */ - width: 200px; /* in pixels */ - font-size: 20pt; /* in points */ - width: 5cm; /* in centimeters */ - min-width: 50mm; /* in millimeters */ - max-width: 5in; /* in inches. max-(width|height) */ - height: 0.2vh; /* times vertical height of browser viewport (CSS3) */ - width: 0.4vw; /* times horizontal width of browser viewport (CSS3) */ - min-height: 0.1vmin; /* the lesser of vertical, horizontal dimensions of browser viewport (CSS3) */ - max-width: 0.3vmax; /* same as above, except the greater of the dimensions (CSS3) */ - + + /* Units of length can be absolute or relative. */ + + /* Relative units */ + width: 50%; /* percentage of parent element width */ + font-size: 2em; /* multiples of element's original font-size */ + font-size: 2rem; /* or the root element's font-size */ + font-size: 2vw; /* multiples of 1% of the viewport's width (CSS 3) */ + font-size: 2vh; /* or its height */ + font-size: 2vmin; /* whichever of a vh or a vw is smaller */ + font-size: 2vmax; /* or greater */ + + /* Absolute units */ + width: 200px; /* pixels */ + font-size: 20pt; /* points */ + width: 5cm; /* centimeters */ + min-width: 50mm; /* millimeters */ + max-width: 5in; /* inches */ + /* Colors */ - background-color: #F6E; /* in short hex */ - background-color: #F262E2; /* in long hex format */ - background-color: tomato; /* can be a named color */ - background-color: rgb(255, 255, 255); /* in rgb */ - background-color: rgb(10%, 20%, 50%); /* in rgb percent */ - background-color: rgba(255, 0, 0, 0.3); /* in semi-transparent rgb (CSS3) */ - background-color: transparent; /* see thru */ - background-color: hsl(0, 100%, 50%); /* hsl format (CSS3). */ - background-color: hsla(0, 100%, 50%, 0.3); /* Similar to RGBA, specify opacity at end (CSS3) */ - - - /* Images */ - background-image: url(/path-to-image/image.jpg); /* quotes inside url() optional */ - + color: #F6E; /* short hex format */ + color: #FF66EE; /* long hex format */ + color: tomato; /* a named color */ + color: rgb(255, 255, 255); /* as rgb values */ + color: rgb(10%, 20%, 50%); /* as rgb percentages */ + color: rgba(255, 0, 0, 0.3); /* as rgba values (CSS 3) Note: 0 < a < 1 */ + color: transparent; /* equivalent to setting the alpha to 0 */ + color: hsl(0, 100%, 50%); /* as hsl percentages (CSS 3) */ + color: hsla(0, 100%, 50%, 0.3); /* as hsla percentages with alpha */ + + /* Images as backgrounds of elements */ + background-image: url(/img-path/img.jpg); /* quotes inside url() optional */ + /* Fonts */ font-family: Arial; - font-family: "Courier New"; /* if name has space it appears in single or double quotes */ - font-family: "Courier New", Trebuchet, Arial, sans-serif; /* if first one was not found - browser uses the second font, and so forth */ + /* if the font family name has a space, it must be quoted */ + font-family: "Courier New"; + /* if the first one is not found, the browser uses the next, and so on */ + font-family: "Courier New", Trebuchet, Arial, sans-serif; } - ``` ## Usage -Save any CSS you want in a file with extension `.css`. +Save a CSS stylesheet with the extension `.css`. ```xml -<!-- you need to include the css file in your page's <head>: --> +<!-- You need to include the css file in your page's <head>. This is the + recommended method. Refer to http://stackoverflow.com/questions/8284365 --> <link rel='stylesheet' type='text/css' href='path/to/style.css' /> -<!-- you can also include some CSS inline in your markup. However it is highly -recommended to avoid this. --> +<!-- You can also include some CSS inline in your markup. --> <style> a { color: purple; } </style> -<!-- or directly set CSS properties on the element. -This has to be avoided as much as you can. --> +<!-- Or directly set CSS properties on the element. --> <div style="border: 1px solid red;"> </div> - ``` -## Precedence +## Precedence or Cascade + +An element may be targeted by multiple selectors and may have a property set on it in more than once. In these cases, one of the rules takes precedence over others. Generally, a rule in a more specific selector take precedence over a less specific one, and a rule occuring later in the stylesheet overwrites a previous one. -As you noticed an element may be targetted by more than one selector. -and may have a property set on it in more than one. -In these cases, one of the rules takes precedence over others. +This process is called cascading, hence the name Cascading Style Sheets. Given the following CSS: ```css -/*A*/ +/* A */ p.class1[attr='value'] -/*B*/ -p.class1 {} +/* B */ +p.class1 { } -/*C*/ -p.class2 {} +/* C */ +p.class2 { } -/*D*/ -p {} +/* D */ +p { } -/*E*/ +/* E */ p { property: value !important; } - ``` and the following markup: ```xml -<p style='/*F*/ property:value;' class='class1 class2' attr='value'> -</p> +<p style='/*F*/ property:value;' class='class1 class2' attr='value' /> ``` -The precedence of style is as followed: -Remember, the precedence is for each **property**, not for the entire block. +The precedence of style is as follows. Remember, the precedence is for each **property**, not for the entire block. -* `E` has the highest precedence because of the keyword `!important`. - It is recommended to avoid this unless it is strictly necessary to use. -* `F` is next, because it is inline style. -* `A` is next, because it is more "specific" than anything else. - more specific = more specifiers. here 3 specifiers: 1 tagname `p` + - class name `class1` + 1 attribute `attr='value'` -* `C` is next. although it has the same specificness as `B` - but it appears last. -* Then is `B` -* and lastly is `D`. +* `E` has the highest precedence because of the keyword `!important`. It is recommended that you avoid its usage. +* `F` is next, because it is an inline style. +* `A` is next, because it is more "specific" than anything else. It has 3 specifiers: The name of the element `p`, its class `class1`, an attribute `attr='value'`. +* `C` is next, even though it has the same specificity as `B`. This is because it appears after `B`. +* `B` is next. +* `D` is the last one. ## Compatibility -Most of the features in CSS2 (and gradually in CSS3) are compatible across -all browsers and devices. But it's always vital to have in mind the compatibility -of what you use in CSS with your target browsers. +Most of the features in CSS 2 (and many in CSS 3) are available across all browsers and devices. But it's always good practice to check before using a new feature. -[QuirksMode CSS](http://www.quirksmode.org/css/) is one of the best sources for this. +## Resources -To run a quick compatibility check, [Can I Use...](http://caniuse.com) is a great resource. +* To run a quick compatibility check, [CanIUse](http://caniuse.com). +* CSS Playground [Dabblet](http://dabblet.com/). +* [Mozilla Developer Network's CSS documentation](https://developer.mozilla.org/en-US/docs/Web/CSS) +* [Codrops' CSS Reference](http://tympanus.net/codrops/css_reference/) ## Further Reading -* [Mozilla Developer Network's CSS documentation](https://developer.mozilla.org/en-US/docs/Web/CSS) -* [Codrops' CSS Reference](http://tympanus.net/codrops/css_reference/) * [Understanding Style Precedence in CSS: Specificity, Inheritance, and the Cascade](http://www.vanseodesign.com/css/css-specificity-inheritance-cascaade/) +* [Selecting elements using attributes](https://css-tricks.com/almanac/selectors/a/attribute/) * [QuirksMode CSS](http://www.quirksmode.org/css/) * [Z-Index - The stacking context](https://developer.mozilla.org/en-US/docs/Web/Guide/CSS/Understanding_z_index/The_stacking_context) -* [SCSS](http://sass-lang.com/) and [LESS](http://lesscss.org/) for CSS pre-processing +* [SASS](http://sass-lang.com/) and [LESS](http://lesscss.org/) for CSS pre-processing +* [CSS-Tricks](https://css-tricks.com) diff --git a/d.html.markdown b/d.html.markdown index ba24b60f..88a83e41 100644 --- a/d.html.markdown +++ b/d.html.markdown @@ -23,8 +23,10 @@ about [D](http://dlang.org/). The D programming language is a modern, general-pu multi-paradigm language with support for everything from low-level features to expressive high-level abstractions. -D is actively developed by Walter Bright and Andrei Alexandrescu, two super smart, really cool -dudes. With all that out of the way, let's look at some examples! +D is actively developed by a large group of super-smart people and is spearheaded by +[Walter Bright](https://en.wikipedia.org/wiki/Walter_Bright) and +[Andrei Alexandrescu](https://en.wikipedia.org/wiki/Andrei_Alexandrescu). +With all that out of the way, let's look at some examples! ```c import std.stdio; @@ -36,9 +38,10 @@ void main() { writeln(i); } - auto n = 1; // use auto for type inferred variables + // 'auto' can be used for inferring types. + auto n = 1; - // Numeric literals can use _ as a digit seperator for clarity + // Numeric literals can use '_' as a digit separator for clarity. while(n < 10_000) { n += n; } @@ -47,13 +50,15 @@ void main() { n -= (n / 2); } while(n > 0); - // For and while are nice, but in D-land we prefer foreach - // The .. creates a continuous range, excluding the end + // For and while are nice, but in D-land we prefer 'foreach' loops. + // The '..' creates a continuous range, including the first value + // but excluding the last. foreach(i; 1..1_000_000) { if(n % 2 == 0) writeln(i); } + // There's also 'foreach_reverse' when you want to loop backwards. foreach_reverse(i; 1..int.max) { if(n % 2 == 1) { writeln(i); @@ -78,7 +83,7 @@ struct LinkedList(T) { class BinTree(T) { T data = null; - // If there is only one template parameter, we can omit parens + // If there is only one template parameter, we can omit the parentheses BinTree!T left; BinTree!T right; } diff --git a/fr-fr/haml-fr.html.markdown b/fr-fr/haml-fr.html.markdown index 0267a380..24be8bf9 100644 --- a/fr-fr/haml-fr.html.markdown +++ b/fr-fr/haml-fr.html.markdown @@ -4,6 +4,7 @@ filename: learnhaml.haml contributors: - ["Simon Neveu", "https://github.com/sneveu"] - ["Thibault", "https://github.com/iTech-"] +lang: fr-fr --- Haml est un langage de balisage utilisé majoritairement avec Ruby, qui décrit de manière simple et propre le HTML de n'importe quelle page web sans l'utilisation des traditionnelles lignes de code. Le langage est une alternative très populaire au langage de templates Rails (.erb) et permet d'intégrer du code en Ruby dans votre balisage. diff --git a/fr-fr/objective-c-fr.html.markdown b/fr-fr/objective-c-fr.html.markdown index 69f4d8f9..4e31c4bf 100644 --- a/fr-fr/objective-c-fr.html.markdown +++ b/fr-fr/objective-c-fr.html.markdown @@ -14,7 +14,7 @@ lang: fr-fr L'Objective-C est un langage de programmation orienté objet réflexif principalement utilisé par Apple pour les systèmes d'exploitations Mac OS X et iOS et leurs frameworks respectifs, Cocoa et Cocoa Touch. -```objective_c +```objective-c // Les commentaires sur une seule ligne commencent par // /* diff --git a/git.html.markdown b/git.html.markdown index 72079f6c..971d53e4 100644 --- a/git.html.markdown +++ b/git.html.markdown @@ -5,6 +5,7 @@ contributors: - ["Jake Prather", "http://github.com/JakeHP"] - ["Leo Rudberg" , "http://github.com/LOZORD"] - ["Betsy Lorton" , "http://github.com/schbetsy"] + - ["Bruno Volcov", "http://github.com/volcov"] filename: LearnGit.txt --- @@ -76,6 +77,11 @@ other repositories, or not! A branch is essentially a pointer to the last commit you made. As you go on committing, this pointer will automatically update to point the latest commit. +### Tag + +A tag is a mark on specific point in history. Typically people use this +functionality to mark release points (v1.0, and so on) + ### HEAD and head (component of .git dir) HEAD is a pointer that points to the current branch. A repository only has 1 *active* HEAD. @@ -206,6 +212,28 @@ $ git branch -m myBranchName myNewBranchName $ git branch myBranchName --edit-description ``` +### tag + +Manage your tags + +```bash +# List tags +$ git tag +# Create a annotated tag +# The -m specifies a tagging message,which is stored with the tag. +# If you don’t specify a message for an annotated tag, +# Git launches your editor so you can type it in. +$ git tag -a v2.0 -m 'my version 2.0' +# Show info about tag +# That shows the tagger information, the date the commit was tagged, +# and the annotation message before showing the commit information. +$ git show v2.0 +# Push a single tag to remote +$ git push origin v2.0 +# Push a lot of tags to remote +$ git push origin --tags +``` + ### checkout Updates all files in the working tree to match the version in the index, or specified tree. diff --git a/go.html.markdown b/go.html.markdown index 646a5650..a857a76c 100644 --- a/go.html.markdown +++ b/go.html.markdown @@ -423,3 +423,5 @@ idioms. Or you can click on a function name in [the documentation](http://golang.org/pkg/) and the source code comes up! Another great resource to learn Go is [Go by example](https://gobyexample.com/). + +Go Mobile adds support for mobile platforms (Android and iOS). You can write all-Go native mobile apps or write a library that contains bindings from a Go package, which can be invoked via Java (Android) and Objective-C (iOS). Check out the [Go Mobile page](https://github.com/golang/go/wiki/Mobile) for more information. diff --git a/haml.html.markdown b/haml.html.markdown index 847714e6..0948e9ef 100644 --- a/haml.html.markdown +++ b/haml.html.markdown @@ -122,11 +122,36 @@ $ haml input_file.haml output_file.html if book do %p This is a book + +/ Adding ordered / unordered list +%ul + %li + =item1 + =item2 / Again, no need to add the closing tags to the block, even for the Ruby. Indentation will take care of that for you. +/ ------------------------------------------- +/ Inserting Table with bootstrap classes +/ ------------------------------------------- + +%table.table.table-hover + %thead + %tr + %th Header 1 + %th Header 2 + + %tr + %td Value1 + %td value2 + + %tfoot + %tr + %td + Foot value + / ------------------------------------------- / Inline Ruby / Ruby interpolation diff --git a/java.html.markdown b/java.html.markdown index 67e5494e..35ec57d8 100644 --- a/java.html.markdown +++ b/java.html.markdown @@ -6,6 +6,7 @@ contributors: - ["Madison Dickson", "http://github.com/mix3d"] - ["Simon Morgan", "http://sjm.io/"] - ["Zachary Ferguson", "http://github.com/zfergus2"] + - ["Cameron Schermerhorn", "http://github.com/cschermerhorn"] filename: LearnJava.java --- @@ -95,11 +96,13 @@ public class LearnJava { // Note: Java has no unsigned types. // Float - Single-precision 32-bit IEEE 754 Floating Point + // 2^-149 <= float <= (2-2^-23) * 2^127 float fooFloat = 234.5f; // f or F is used to denote that this variable value is of type float; // otherwise it is treated as double. // Double - Double-precision 64-bit IEEE 754 Floating Point + // 2^-1074 <= x <= (2-2^-52) * 2^1023 double fooDouble = 123.4; // Boolean - true & false @@ -115,6 +118,34 @@ public class LearnJava { final double E; E = 2.71828; + + // BigInteger - Immutable arbitrary-precision integers + // + // BigInteger is a data type that allows programmers to manipulate + // integers longer than 64-bits. Integers are stored as an array of + // of bytes and are manipulated using functions built into BigInteger + // + // BigInteger can be initialized using an array of bytes or a string. + + BigInteger fooBigInteger = new BigDecimal(fooByteArray); + + + // BigDecimal - Immutable, arbitrary-precision signed decimal number + // + // A BigDecimal takes two parts: an arbitrary precision integer + // unscaled value and a 32-bit integer scale + // + // BigDecimal allows the programmer complete control over decimal + // rounding. It is recommended to use BigDecimal with currency values + // and where exact decimal percision is required. + // + // BigDecimal can be initialized with an int, long, double or String + // or by initializing the unscaled value (BigInteger) and scale (int). + + BigDecimal fooBigDecimal = new BigDecimal(fooBigInteger, fooInt); + + + // Strings String fooString = "My String Is Here!"; @@ -286,6 +317,23 @@ public class LearnJava { break; } System.out.println("Switch Case Result: " + monthString); + + // Starting in Java 7 and above, switching Strings works like this: + String myAnswer = "maybe"; + switch(myAnswer){ + case "yes": + System.out.println("You answered yes."); + break; + case "no": + System.out.println("You answered no."); + break; + case "maybe": + System.out.println("You answered maybe."); + break; + default: + System.out.println("You answered " + myAnswer); + break; + } // Conditional Shorthand // You can use the '?' operator for quick assignments or logic forks. diff --git a/json.html.markdown b/json.html.markdown index a1629137..060e9c3d 100644 --- a/json.html.markdown +++ b/json.html.markdown @@ -4,6 +4,7 @@ filename: learnjson.json contributors: - ["Anna Harren", "https://github.com/iirelu"] - ["Marco Scannadinari", "https://github.com/marcoms"] + - ["himanshu", "https://github.com/himanshu81494"] --- As JSON is an extremely simple data-interchange format, this is most likely going @@ -16,6 +17,11 @@ but they should be avoided for better compatibility. For the purposes of this, however, everything is going to be 100% valid JSON. Luckily, it kind of speaks for itself. +Data types supported by JSON includes: numbers, string, boolean, array, object and null. +Supporting browsers are: Firefox(Mozilla) 3.5, Internet Explorer 8, Chrome, Opera 10, Safari 4. +JSON file type for JSON files is ".json". The MIME type for JSON text is "application/json" +Drawbacks of JSON include lack of type definition and some sort of DTD. + ```json { "key": "value", @@ -52,7 +58,7 @@ For the purposes of this, however, everything is going to be 100% valid JSON. Lu "alternative style": { "comment": "check this out!" - , "comma position": "doesn't matter - as long as it's before the value, then it's valid" + , "comma position": "doesn't matter - as long as it's before the next key, then it's valid" , "another comment": "how nice" }, diff --git a/latex.html.markdown b/latex.html.markdown new file mode 100644 index 00000000..146e8d45 --- /dev/null +++ b/latex.html.markdown @@ -0,0 +1,231 @@ +--- +language: latex +contributors: + - ["Chaitanya Krishna Ande", "http://icymist.github.io"] + - ["Colton Kohnke", "http://github.com/voltnor"] + - ["Sricharan Chiruvolu", "http://sricharan.xyz"] +filename: learn-latex.tex +--- +% All comment lines start with % +% There are no multi-line comments + +% LaTeX is NOT a "What You See Is What You Get" word processing software like +% MS Word, or OpenOffice Writer + +% Every Latex command starts with a backslash (\) + +% LaTeX documents start with a defining the type of document it's compiling +% Other document types include book, report, presentations, etc. +% The options for the document appear in the [] brackets. In this case +% it specifies we want to use 12pt font. +\documentclass[12pt]{article} + +% Next we define the packages the document uses. +% If you want to include graphics, colored text, or +% source code from another language file into your document, +% you need to enhance the capabilities of LaTeX. This is done by adding packages. +% I'm going to include the float and caption packages for figures. +\usepackage{caption} +\usepackage{float} + +% We can define some other document properties too! +\author{Chaitanya Krishna Ande, Colton Kohnke \& Sricharan Chiruvolu} +\date{\today} +\title{Learn LaTeX in Y Minutes!} + +% Now we're ready to begin the document +% Everything before this line is called "The Preamble" +\begin{document} +% if we set the author, date, title fields, we can have LaTeX +% create a title page for us. +\maketitle + +% Most research papers have abstract, you can use the predefined commands for this. +% This should appear in its logical order, therefore, after the top matter, +% but before the main sections of the body. +% This command is available in the document classes article and report. +\begin{abstract} + LaTex documentation written as LaTex! How novel and totally not my idea! +\end{abstract} + +% Section commands are intuitive. +% All the titles of the sections are added automatically to the table of contents. +\section{Introduction} +Hello, my name is Colton and together we're going to explore LaTeX! + +\section{Another section} +This is the text for another section. I think it needs a subsection. + +\subsection{This is a subsection} % Subsections are also intuitive. +I think we need another one + +\subsubsection{Pythagoras} +Much better now. +\label{subsec:pythagoras} + +% By using the asterisk we can suppress Latex's inbuilt numbering. +% This works for other Latex commands as well. +\section*{This is an unnumbered section} +However not all sections have to be numbered! + +\section{Some Text notes} +LaTeX is generally pretty good about placing text where it should go. If +a line \\ needs \\ to \\ break \\ you add \textbackslash\textbackslash to +the source code. \\ + +\section{Lists} +Lists are one of the easiest things to create in Latex! I need to go shopping +tomorrow, so let's make a grocery list. +\begin{enumerate} % This creates an "enumerate" environment. + % \item tells the enumerate to increment + \item Salad. + \item 27 watermelon. + \item A single jackrabbit. + % we can even override the item number by using [] + \item[how many?] Medium sized squirt guns. + + Not a list item, but still part of the enumerate. + +\end{enumerate} % All environments must have an end. + +\section{Math} + +One of the primary uses for LaTeX is to produce academic articles or +technical papers. Usually in the realm of math and science. As such, +we need to be able to add special symbols to our paper! \\ + +Math has many symbols, far beyond what you can find on a keyboard; +Set and relation symbols, arrows, operators, and Greek letters to name a few.\\ + +Sets and relations play a vital role in many mathematical research papers. +Here's how you state all y that belong to X, $\forall$ x $\in$ X. \\ +% Notice how I needed to add $ signs before and after the symbols. This is +% because when writing, we are in text-mode. +% However, the math symbols only exist in math-mode. +% We can enter math-mode from text mode with the $ signs. +% The opposite also holds true. Variable can also be rendered in math-mode. + +My favorite Greek letter is $\xi$. I also like $\beta$, $\gamma$ and $\sigma$. +I haven't found a Greek letter that yet that Latex doesn't know about! + +Operators are essential parts of a mathematical document: +trigonometric functions ($\sin$, $\cos$, $\tan$), +logarithms and exponentials ($\log$, $\exp$), +limits ($\lim$), etc. +have per-defined LaTeX commands. +Let's write an equation to see how it's done: \\ + +$\cos(2\theta) = \cos^{2}(\theta) - \sin^{2}(\theta)$ + +Fractions(Numerator-denominators) can be written in these forms: + +% 10 / 7 +$^{10}/_{7}$ + +% Relatively complex fractions can be written as +% \frac{numerator}{denominator} +$\frac{n!}{k!(n - k)!}$ \\ + +We can also insert equations in an "equation environment." + +% Display math with the equation 'environment' +\begin{equation} % enters math-mode + c^2 = a^2 + b^2. + \label{eq:pythagoras} % for referencing +\end{equation} % all \begin statements must have an end statement + +We can then reference our new equation! +Eqn.~\ref{eq:pythagoras} is also known as the Pythagoras Theorem which is also +the subject of Sec.~\ref{subsec:pythagoras}. A lot of things can be labeled: +figures, equations, sections, etc. + +Summations and Integrals are written with sum and int commands: + +% Some latex compilers will complain if there are blank lines +% In an equation environment. +\begin{equation} + \sum_{i=0}^{5} f_{i} +\end{equation} +\begin{equation} + \int_{0}^{\infty} \mathrm{e}^{-x} \mathrm{d}x +\end{equation} + +\section{Figures} + +Let's insert a Figure. Figure placement can get a little tricky. +I definitely have to lookup the placement options each time. + +\begin{figure}[H] % H here denoted the placement option. + \centering % centers the figure on the page + % Inserts a figure scaled to 0.8 the width of the page. + %\includegraphics[width=0.8\linewidth]{right-triangle.png} + % Commented out for compilation purposes. Please use your imagination. + \caption{Right triangle with sides $a$, $b$, $c$} + \label{fig:right-triangle} +\end{figure} + +\subsection{Table} +We can also insert Tables in the same way as figures. + +\begin{table}[H] + \caption{Caption for the Table.} + % the {} arguments below describe how each row of the table is drawn. + % Again, I have to look these up. Each. And. Every. Time. + \begin{tabular}{c|cc} + Number & Last Name & First Name \\ % Column rows are separated by $ + \hline % a horizontal line + 1 & Biggus & Dickus \\ + 2 & Monty & Python + \end{tabular} +\end{table} + +% \section{Hyperlinks} % Coming soon + +\section{Getting Latex to not compile something (i,e, Source Code)} +Let's say we want to include some code into our Latex document, +we would then need Latex to not try and interpret that text and +instead just print it to the document. We do this we a verbatim +environment. + +% There are other packages that exist (i.e. minty, lstlisting, etc.) +% but verbatim is the bare-bones basic one. +\begin{verbatim} + print("Hello World!") + a%b; % look! We can use % signs in verbatim. + random = 4; #decided by fair random dice roll +\end{verbatim} + +\section{Compiling} + +By now you're probably wondering how to compile this fabulous document +and look at the glorious glory that is a Latex pdf. +(yes, this document actually does compiles). \\ +Getting to the final document using LaTeX consists of the following steps: + \begin{enumerate} + \item Write the document in plain text (the "source code"). + \item Compile source code to produce a pdf. + The compilation step looks something like this (in Linux): \\ + \begin{verbatim} + $pdflatex learn-latex.tex learn-latex.pdf + \end{verbatim} + \end{enumerate} + +A number of LaTeX editors combine both Step 1 and Step 2 in the same piece of +software. So, you get to see Step 1, but not Step 2 completely. +Step 2 is still happening behind the scenes. + +You write all your formatting information in plain text in Step 1. +The compilation part in Step 2 takes care of producing the document in the +format you defined in Step 1. + +\section{End} + +That's all for now! + +% end the document +\end{document} +``` +## More on LaTeX + +* The amazing LaTeX wikibook: [https://en.wikibooks.org/wiki/LaTeX](https://en.wikibooks.org/wiki/LaTeX) +* An actual tutorial: [http://www.latex-tutorial.com/](http://www.latex-tutorial.com/) diff --git a/objective-c.html.markdown b/objective-c.html.markdown index 89901308..cf6bf780 100644 --- a/objective-c.html.markdown +++ b/objective-c.html.markdown @@ -13,7 +13,7 @@ filename: LearnObjectiveC.m Objective-C is the main programming language used by Apple for the OS X and iOS operating systems and their respective frameworks, Cocoa and Cocoa Touch. It is a general-purpose, object-oriented programming language that adds Smalltalk-style messaging to the C programming language. -```objective_c +```objective-c // Single-line comments start with // /* diff --git a/python.html.markdown b/python.html.markdown index 6cfb5dca..b939ebbe 100644 --- a/python.html.markdown +++ b/python.html.markdown @@ -14,7 +14,13 @@ executable pseudocode. Feedback would be highly appreciated! You can reach me at [@louiedinh](http://twitter.com/louiedinh) or louiedinh [at] [google's email service] Note: This article applies to Python 2.7 specifically, but should be applicable -to Python 2.x. For Python 3.x, take a look at the [Python 3 tutorial](http://learnxinyminutes.com/docs/python3/). +to Python 2.x. Python 2.7 is reachong end of life and will stop beeign maintained in 2020, +it is though recommended to start learnign Python with Python 3. +For Python 3.x, take a look at the [Python 3 tutorial](http://learnxinyminutes.com/docs/python3/). + +It is also possible to write Python code which is compatible with Python 2.7 and 3.x at the same time, +using Python [`__future__` imports](https://docs.python.org/2/library/__future__.html). `__future__` imports +allow you to write Python 3 code that will run on Python 2, so check out the Python 3 tutorial. ```python @@ -142,7 +148,13 @@ bool("") # => False #################################################### # Python has a print statement -print "I'm Python. Nice to meet you!" +print "I'm Python. Nice to meet you!" # => I'm Python. Nice to meet you! + +# Simple way to get input data from console +input_string_var = raw_input("Enter some data: ") # Returns the data as a string +input_var = input("Enter some data: ") # Evaluates the data as python code +# Warning: Caution is recommended for input() method usage +# Note: In python 3, input() is deprecated and raw_input() is renamed to input() # No need to declare variables before assigning to them. some_var = 5 # Convention is to use lower_case_with_underscores diff --git a/python3.html.markdown b/python3.html.markdown index 5a992b54..f3f4dd37 100644 --- a/python3.html.markdown +++ b/python3.html.markdown @@ -33,27 +33,27 @@ Note: This article applies to Python 3 specifically. Check out [here](http://lea 3 # => 3 # Math is what you would expect -1 + 1 # => 2 -8 - 1 # => 7 +1 + 1 # => 2 +8 - 1 # => 7 10 * 2 # => 20 # Except division which returns floats, real numbers, by default 35 / 5 # => 7.0 # Result of integer division truncated down both for positive and negative. -5 // 3 # => 1 -5.0 // 3.0 # => 1.0 # works on floats too --5 // 3 # => -2 --5.0 // 3.0 # => -2.0 +5 // 3 # => 1 +5.0 // 3.0 # => 1.0 # works on floats too +-5 // 3 # => -2 +-5.0 // 3.0 # => -2.0 # When you use a float, results are floats -3 * 2.0 # => 6.0 +3 * 2.0 # => 6.0 # Modulo operation -7 % 3 # => 1 +7 % 3 # => 1 # Exponentiation (x**y, x to the yth power) -2**4 # => 16 +2**4 # => 16 # Enforce precedence with parentheses (1 + 3) * 2 # => 8 @@ -63,20 +63,20 @@ True False # negate with not -not True # => False +not True # => False not False # => True # Boolean Operators # Note "and" and "or" are case-sensitive -True and False #=> False -False or True #=> True +True and False # => False +False or True # => True # Note using Bool operators with ints -0 and 2 #=> 0 --5 or 0 #=> -5 -0 == False #=> True -2 == True #=> False -1 == True #=> True +0 and 2 # => 0 +-5 or 0 # => -5 +0 == False # => True +2 == True # => False +1 == True # => True # Equality is == 1 == 1 # => True @@ -98,13 +98,13 @@ False or True #=> True # (is vs. ==) is checks if two variable refer to the same object, but == checks # if the objects pointed to have the same values. -a = [1, 2, 3, 4] # Point a at a new list, [1, 2, 3, 4] -b = a # Point b at what a is pointing to -b is a # => True, a and b refer to the same object -b == a # => True, a's and b's objects are equal -b = [1, 2, 3, 4] # Point a at a new list, [1, 2, 3, 4] -b is a # => False, a and b do not refer to the same object -b == a # => True, a's and b's objects are equal +a = [1, 2, 3, 4] # Point a at a new list, [1, 2, 3, 4] +b = a # Point b at what a is pointing to +b is a # => True, a and b refer to the same object +b == a # => True, a's and b's objects are equal +b = [1, 2, 3, 4] # Point a at a new list, [1, 2, 3, 4] +b is a # => False, a and b do not refer to the same object +b == a # => True, a's and b's objects are equal # Strings are created with " or ' "This is a string." @@ -113,24 +113,24 @@ b == a # => True, a's and b's objects are equal # Strings can be added too! But try not to do this. "Hello " + "world!" # => "Hello world!" # Strings can be added without using '+' -"Hello " "world!" # => "Hello world!" +"Hello " "world!" # => "Hello world!" # A string can be treated like a list of characters "This is a string"[0] # => 'T' # .format can be used to format strings, like this: -"{} can be {}".format("strings", "interpolated") +"{} can be {}".format("Strings", "interpolated") # => "Strings can be interpolated" # You can repeat the formatting arguments to save some typing. "{0} be nimble, {0} be quick, {0} jump over the {1}".format("Jack", "candle stick") -#=> "Jack be nimble, Jack be quick, Jack jump over the candle stick" +# => "Jack be nimble, Jack be quick, Jack jump over the candle stick" # You can use keywords if you don't want to count. -"{name} wants to eat {food}".format(name="Bob", food="lasagna") #=> "Bob wants to eat lasagna" +"{name} wants to eat {food}".format(name="Bob", food="lasagna") # => "Bob wants to eat lasagna" # If your Python 3 code also needs to run on Python 2.5 and below, you can also # still use the old style of formatting: -"%s can be %s the %s way" % ("strings", "interpolated", "old") +"%s can be %s the %s way" % ("Strings", "interpolated", "old") # => "Strings can be interpolated the old way" # None is an object @@ -139,14 +139,14 @@ None # => None # Don't use the equality "==" symbol to compare objects to None # Use "is" instead. This checks for equality of object identity. "etc" is None # => False -None is None # => True +None is None # => True # None, 0, and empty strings/lists/dicts all evaluate to False. # All other values are True -bool(0) # => False +bool(0) # => False bool("") # => False -bool([]) #=> False -bool({}) #=> False +bool([]) # => False +bool({}) # => False #################################################### @@ -154,11 +154,11 @@ bool({}) #=> False #################################################### # Python has a print function -print("I'm Python. Nice to meet you!") +print("I'm Python. Nice to meet you!") # => I'm Python. Nice to meet you! # By default the print function also prints out a newline at the end. # Use the optional argument end to change the end character. -print("Hello, World", end="!") # => Hello, World! +print("Hello, World", end="!") # => Hello, World! # No need to declare variables before assigning to them. # Convention is to use lower_case_with_underscores @@ -185,7 +185,7 @@ li.pop() # => 3 and li is now [1, 2, 4] li.append(3) # li is now [1, 2, 4, 3] again. # Access a list like you would any array -li[0] # => 1 +li[0] # => 1 # Look at the last element li[-1] # => 3 @@ -194,61 +194,61 @@ li[4] # Raises an IndexError # You can look at ranges with slice syntax. # (It's a closed/open range for you mathy types.) -li[1:3] # => [2, 4] +li[1:3] # => [2, 4] # Omit the beginning -li[2:] # => [4, 3] +li[2:] # => [4, 3] # Omit the end -li[:3] # => [1, 2, 4] +li[:3] # => [1, 2, 4] # Select every second entry li[::2] # =>[1, 4] # Return a reversed copy of the list -li[::-1] # => [3, 4, 2, 1] +li[::-1] # => [3, 4, 2, 1] # Use any combination of these to make advanced slices # li[start:end:step] # Make a one layer deep copy using slices -li2 = li[:] # => li2 = [1, 2, 4, 3] but (li2 is li) will result in false. +li2 = li[:] # => li2 = [1, 2, 4, 3] but (li2 is li) will result in false. # Remove arbitrary elements from a list with "del" -del li[2] # li is now [1, 2, 3] +del li[2] # li is now [1, 2, 3] # You can add lists # Note: values for li and for other_li are not modified. -li + other_li # => [1, 2, 3, 4, 5, 6] +li + other_li # => [1, 2, 3, 4, 5, 6] # Concatenate lists with "extend()" -li.extend(other_li) # Now li is [1, 2, 3, 4, 5, 6] +li.extend(other_li) # Now li is [1, 2, 3, 4, 5, 6] # Check for existence in a list with "in" -1 in li # => True +1 in li # => True # Examine the length with "len()" -len(li) # => 6 +len(li) # => 6 # Tuples are like lists but are immutable. tup = (1, 2, 3) -tup[0] # => 1 +tup[0] # => 1 tup[0] = 3 # Raises a TypeError # Note that a tuple of length one has to have a comma after the last element but # tuples of other lengths, even zero, do not. -type((1)) # => <class 'int'> -type((1,)) # => <class 'tuple'> -type(()) # => <class 'tuple'> +type((1)) # => <class 'int'> +type((1,)) # => <class 'tuple'> +type(()) # => <class 'tuple'> # You can do most of the list operations on tuples too -len(tup) # => 3 -tup + (4, 5, 6) # => (1, 2, 3, 4, 5, 6) -tup[:2] # => (1, 2) -2 in tup # => True +len(tup) # => 3 +tup + (4, 5, 6) # => (1, 2, 3, 4, 5, 6) +tup[:2] # => (1, 2) +2 in tup # => True # You can unpack tuples (or lists) into variables -a, b, c = (1, 2, 3) # a is now 1, b is now 2 and c is now 3 +a, b, c = (1, 2, 3) # a is now 1, b is now 2 and c is now 3 # Tuples are created by default if you leave out the parentheses d, e, f = 4, 5, 6 # Now look how easy it is to swap two values -e, d = d, e # d is now 5 and e is now 4 +e, d = d, e # d is now 5 and e is now 4 # Dictionaries store mappings @@ -259,45 +259,45 @@ filled_dict = {"one": 1, "two": 2, "three": 3} # Note keys for dictionaries have to be immutable types. This is to ensure that # the key can be converted to a constant hash value for quick look-ups. # Immutable types include ints, floats, strings, tuples. -invalid_dict = {[1,2,3]: "123"} # => Raises a TypeError: unhashable type: 'list' -valid_dict = {(1,2,3):[1,2,3]} # Values can be of any type, however. +invalid_dict = {[1,2,3]: "123"} # => Raises a TypeError: unhashable type: 'list' +valid_dict = {(1,2,3):[1,2,3]} # Values can be of any type, however. # Look up values with [] -filled_dict["one"] # => 1 +filled_dict["one"] # => 1 # Get all keys as an iterable with "keys()". We need to wrap the call in list() # to turn it into a list. We'll talk about those later. Note - Dictionary key # ordering is not guaranteed. Your results might not match this exactly. -list(filled_dict.keys()) # => ["three", "two", "one"] +list(filled_dict.keys()) # => ["three", "two", "one"] # Get all values as an iterable with "values()". Once again we need to wrap it # in list() to get it out of the iterable. Note - Same as above regarding key # ordering. -list(filled_dict.values()) # => [3, 2, 1] +list(filled_dict.values()) # => [3, 2, 1] # Check for existence of keys in a dictionary with "in" -"one" in filled_dict # => True -1 in filled_dict # => False +"one" in filled_dict # => True +1 in filled_dict # => False # Looking up a non-existing key is a KeyError -filled_dict["four"] # KeyError +filled_dict["four"] # KeyError # Use "get()" method to avoid the KeyError -filled_dict.get("one") # => 1 -filled_dict.get("four") # => None +filled_dict.get("one") # => 1 +filled_dict.get("four") # => None # The get method supports a default argument when the value is missing filled_dict.get("one", 4) # => 1 -filled_dict.get("four", 4) # => 4 +filled_dict.get("four", 4) # => 4 # "setdefault()" inserts into a dictionary only if the given key isn't present filled_dict.setdefault("five", 5) # filled_dict["five"] is set to 5 filled_dict.setdefault("five", 6) # filled_dict["five"] is still 5 # Adding to a dictionary -filled_dict.update({"four":4}) #=> {"one": 1, "two": 2, "three": 3, "four": 4} -#filled_dict["four"] = 4 #another way to add to dict +filled_dict.update({"four":4}) # => {"one": 1, "two": 2, "three": 3, "four": 4} +#filled_dict["four"] = 4 #another way to add to dict # Remove keys from a dictionary with del del filled_dict["one"] # Removes the key "one" from filled dict @@ -306,31 +306,31 @@ del filled_dict["one"] # Removes the key "one" from filled dict # Sets store ... well sets empty_set = set() # Initialize a set with a bunch of values. Yeah, it looks a bit like a dict. Sorry. -some_set = {1, 1, 2, 2, 3, 4} # some_set is now {1, 2, 3, 4} +some_set = {1, 1, 2, 2, 3, 4} # some_set is now {1, 2, 3, 4} # Similar to keys of a dictionary, elements of a set have to be immutable. -invalid_set = {[1], 1} # => Raises a TypeError: unhashable type: 'list' +invalid_set = {[1], 1} # => Raises a TypeError: unhashable type: 'list' valid_set = {(1,), 1} # Can set new variables to a set filled_set = some_set # Add one more item to the set -filled_set.add(5) # filled_set is now {1, 2, 3, 4, 5} +filled_set.add(5) # filled_set is now {1, 2, 3, 4, 5} # Do set intersection with & other_set = {3, 4, 5, 6} -filled_set & other_set # => {3, 4, 5} +filled_set & other_set # => {3, 4, 5} # Do set union with | -filled_set | other_set # => {1, 2, 3, 4, 5, 6} +filled_set | other_set # => {1, 2, 3, 4, 5, 6} # Do set difference with - -{1, 2, 3, 4} - {2, 3, 5} # => {1, 4} +{1, 2, 3, 4} - {2, 3, 5} # => {1, 4} # Check for existence in a set with in 2 in filled_set # => True -10 in filled_set # => False +10 in filled_set # => False @@ -416,12 +416,12 @@ try: # Use "raise" to raise an error raise IndexError("This is an index error") except IndexError as e: - pass # Pass is just a no-op. Usually you would do recovery here. + pass # Pass is just a no-op. Usually you would do recovery here. except (TypeError, NameError): - pass # Multiple exceptions can be handled together, if required. -else: # Optional clause to the try/except block. Must follow all except blocks + pass # Multiple exceptions can be handled together, if required. +else: # Optional clause to the try/except block. Must follow all except blocks print("All good!") # Runs only if the code in try raises no exceptions -finally: # Execute under all circumstances +finally: # Execute under all circumstances print("We can clean up resources here") # Instead of try/finally to cleanup resources you can use a with statement @@ -435,11 +435,11 @@ with open("myfile.txt") as f: filled_dict = {"one": 1, "two": 2, "three": 3} our_iterable = filled_dict.keys() -print(our_iterable) #=> range(1,10). This is an object that implements our Iterable interface +print(our_iterable) # => range(1,10). This is an object that implements our Iterable interface # We can loop over it. for i in our_iterable: - print(i) # Prints one, two, three + print(i) # Prints one, two, three # However we cannot address elements by index. our_iterable[1] # Raises a TypeError @@ -449,17 +449,17 @@ our_iterator = iter(our_iterable) # Our iterator is an object that can remember the state as we traverse through it. # We get the next object with "next()". -next(our_iterator) #=> "one" +next(our_iterator) # => "one" # It maintains state as we iterate. -next(our_iterator) #=> "two" -next(our_iterator) #=> "three" +next(our_iterator) # => "two" +next(our_iterator) # => "three" # After the iterator has returned all of its data, it gives you a StopIterator Exception -next(our_iterator) # Raises StopIteration +next(our_iterator) # Raises StopIteration # You can grab all the elements of an iterator by calling list() on it. -list(filled_dict.keys()) #=> Returns ["one", "two", "three"] +list(filled_dict.keys()) # => Returns ["one", "two", "three"] #################################################### @@ -469,20 +469,20 @@ list(filled_dict.keys()) #=> Returns ["one", "two", "three"] # Use "def" to create new functions def add(x, y): print("x is {} and y is {}".format(x, y)) - return x + y # Return values with a return statement + return x + y # Return values with a return statement # Calling functions with parameters -add(5, 6) # => prints out "x is 5 and y is 6" and returns 11 +add(5, 6) # => prints out "x is 5 and y is 6" and returns 11 # Another way to call functions is with keyword arguments -add(y=6, x=5) # Keyword arguments can arrive in any order. +add(y=6, x=5) # Keyword arguments can arrive in any order. # You can define functions that take a variable number of # positional arguments def varargs(*args): return args -varargs(1, 2, 3) # => (1, 2, 3) +varargs(1, 2, 3) # => (1, 2, 3) # You can define functions that take a variable number of # keyword arguments, as well @@ -490,7 +490,7 @@ def keyword_args(**kwargs): return kwargs # Let's call it to see what happens -keyword_args(big="foot", loch="ness") # => {"big": "foot", "loch": "ness"} +keyword_args(big="foot", loch="ness") # => {"big": "foot", "loch": "ness"} # You can do both at once, if you like @@ -507,33 +507,33 @@ all_the_args(1, 2, a=3, b=4) prints: # Use * to expand tuples and use ** to expand kwargs. args = (1, 2, 3, 4) kwargs = {"a": 3, "b": 4} -all_the_args(*args) # equivalent to foo(1, 2, 3, 4) -all_the_args(**kwargs) # equivalent to foo(a=3, b=4) -all_the_args(*args, **kwargs) # equivalent to foo(1, 2, 3, 4, a=3, b=4) +all_the_args(*args) # equivalent to foo(1, 2, 3, 4) +all_the_args(**kwargs) # equivalent to foo(a=3, b=4) +all_the_args(*args, **kwargs) # equivalent to foo(1, 2, 3, 4, a=3, b=4) # Returning multiple values (with tuple assignments) def swap(x, y): - return y, x # Return multiple values as a tuple without the parenthesis. - # (Note: parenthesis have been excluded but can be included) + return y, x # Return multiple values as a tuple without the parenthesis. + # (Note: parenthesis have been excluded but can be included) x = 1 y = 2 -x, y = swap(x, y) # => x = 2, y = 1 -# (x, y) = swap(x,y) # Again parenthesis have been excluded but can be included. +x, y = swap(x, y) # => x = 2, y = 1 +# (x, y) = swap(x,y) # Again parenthesis have been excluded but can be included. # Function Scope x = 5 def setX(num): # Local var x not the same as global variable x - x = num # => 43 - print (x) # => 43 + x = num # => 43 + print (x) # => 43 def setGlobalX(num): global x - print (x) # => 5 - x = num # global var x is now set to 6 - print (x) # => 6 + print (x) # => 5 + x = num # global var x is now set to 6 + print (x) # => 6 setX(43) setGlobalX(6) @@ -549,20 +549,20 @@ add_10 = create_adder(10) add_10(3) # => 13 # There are also anonymous functions -(lambda x: x > 2)(3) # => True -(lambda x, y: x ** 2 + y ** 2)(2, 1) # => 5 +(lambda x: x > 2)(3) # => True +(lambda x, y: x ** 2 + y ** 2)(2, 1) # => 5 # TODO - Fix for iterables # There are built-in higher order functions -map(add_10, [1, 2, 3]) # => [11, 12, 13] -map(max, [1, 2, 3], [4, 2, 1]) # => [4, 2, 3] +map(add_10, [1, 2, 3]) # => [11, 12, 13] +map(max, [1, 2, 3], [4, 2, 1]) # => [4, 2, 3] -filter(lambda x: x > 5, [3, 4, 5, 6, 7]) # => [6, 7] +filter(lambda x: x > 5, [3, 4, 5, 6, 7]) # => [6, 7] # We can use list comprehensions for nice maps and filters # List comprehension stores the output as a list which can itself be a nested list -[add_10(i) for i in [1, 2, 3]] # => [11, 12, 13] -[x for x in [3, 4, 5, 6, 7] if x > 5] # => [6, 7] +[add_10(i) for i in [1, 2, 3]] # => [11, 12, 13] +[x for x in [3, 4, 5, 6, 7] if x > 5] # => [6, 7] #################################################### ## 5. Classes @@ -609,15 +609,15 @@ j = Human("Joel") print(j.say("hello")) # prints out "Joel: hello" # Call our class method -i.get_species() # => "H. sapiens" +i.get_species() # => "H. sapiens" # Change the shared attribute Human.species = "H. neanderthalensis" -i.get_species() # => "H. neanderthalensis" -j.get_species() # => "H. neanderthalensis" +i.get_species() # => "H. neanderthalensis" +j.get_species() # => "H. neanderthalensis" # Call the static method -Human.grunt() # => "*grunt*" +Human.grunt() # => "*grunt*" #################################################### @@ -630,8 +630,8 @@ print(math.sqrt(16)) # => 4 # You can get specific functions from a module from math import ceil, floor -print(ceil(3.7)) # => 4.0 -print(floor(3.7)) # => 3.0 +print(ceil(3.7)) # => 4.0 +print(floor(3.7)) # => 3.0 # You can import all functions from a module. # Warning: this is not recommended @@ -639,7 +639,7 @@ from math import * # You can shorten module names import math as m -math.sqrt(16) == m.sqrt(16) # => True +math.sqrt(16) == m.sqrt(16) # => True # Python modules are just ordinary python files. You # can write your own, and import them. The name of the @@ -664,8 +664,6 @@ def double_numbers(iterable): # Instead of generating and returning all values at once it creates one in each # iteration. This means values bigger than 15 wont be processed in # double_numbers. -# Note range is a generator too. Creating a list 1-900000000 would take lot of -# time to be made # We use a trailing underscore in variable names when we want to use a name that # would normally collide with a python keyword range_ = range(1, 900000000) @@ -700,7 +698,7 @@ def say(say_please=False): return msg, say_please -print(say()) # Can you buy me a beer? +print(say()) # Can you buy me a beer? print(say(say_please=True)) # Can you buy me a beer? Please! I am poor :( ``` @@ -717,6 +715,9 @@ print(say(say_please=True)) # Can you buy me a beer? Please! I am poor :( * [A Crash Course in Python for Scientists](http://nbviewer.ipython.org/5920182) * [Python Course](http://www.python-course.eu/index.php) * [First Steps With Python](https://realpython.com/learn/python-first-steps/) +* [A curated list of awesome Python frameworks, libraries and software](https://github.com/vinta/awesome-python) +* [30 Python Language Features and Tricks You May Not Know About](http://sahandsaba.com/thirty-python-language-features-and-tricks-you-may-not-know.html) +* [Official Style Guide for Python](https://www.python.org/dev/peps/pep-0008/) ### Dead Tree diff --git a/ru-ru/objective-c-ru.html.markdown b/ru-ru/objective-c-ru.html.markdown index ddff2e5c..8eac4ddb 100644 --- a/ru-ru/objective-c-ru.html.markdown +++ b/ru-ru/objective-c-ru.html.markdown @@ -17,7 +17,7 @@ Cocoa Touch. Он является объектно-ориентированным языком программирования общего назначения, который добавляет обмен сообщениями в Smalltalk-стиле к языку программирования C. -```objective_c +```objective-c // Однострочные комментарии начинаются с // /* diff --git a/ru-ru/php-ru.html.markdown b/ru-ru/php-ru.html.markdown index 53b2f916..5672aa90 100644 --- a/ru-ru/php-ru.html.markdown +++ b/ru-ru/php-ru.html.markdown @@ -5,6 +5,7 @@ contributors: - ["Trismegiste", "https://github.com/Trismegiste"] translators: - ["SlaF", "https://github.com/SlaF"] + - ["Corpsee", "https://github.com/corpsee"] lang: ru-ru filename: learnphp-ru.php --- @@ -14,8 +15,8 @@ filename: learnphp-ru.php ```php <?php // PHP код должен быть заключен в теги <?php -// Если ваш файл содержит только PHP код, то можно -// пропустить закрывающийся ?> +// Если ваш файл содержит только PHP-код, то можно +пропустить закрывающий ?> // А так начинаются комментарии @@ -30,10 +31,10 @@ filename: learnphp-ru.php print('Hello '); // Напечатать "Hello " без перевода строки // () необязательно применять для print и echo -echo "World\n"; // Печатать "World" и перейти на новую строку. +echo "World\n"; // Напечатать "World" и перейти на новую строку. // (все утверждения должны заканчиваться ;) -// Любые символы за пределами закрывающегося тега выводятся автоматически: +// Любые символы за пределами закрывающего тега выводятся автоматически: ?> Hello World Again! <?php @@ -46,7 +47,7 @@ Hello World Again! // Переменные начинаются с символа $. // Правильное имя переменной начинается с буквы или знака подчеркивания, // и может содержать любые цифры, буквы, или знаки подчеркивания. -// Не рекомендуется использовать кирилические символы в именах (прим. пер.) +// Не рекомендуется использовать кириллические символы в именах (прим. пер.) // Логические значения нечувствительны к регистру $boolean = true; // или TRUE или True @@ -56,7 +57,7 @@ $boolean = false; // или FALSE или False $int1 = 12; // => 12 $int2 = -12; // => -12- $int3 = 012; // => 10 (ведущий 0 обозначает восьмеричное число) -$int4 = 0x0F; // => 15 (ведущие символы 0x означает шестнадцатеричное число) +$int4 = 0x0F; // => 15 (ведущие символы 0x означают шестнадцатеричное число) // Дробные числа $float = 1.234; @@ -126,7 +127,7 @@ echo 'This outputs '.FOO; // Все массивы в PHP - это ассоциативные массивы или хеши, -// Ассоциативные массивы, известные в других языках как хеш-карты. +// Ассоциативные массивы, известные в других языках как HashMap. // Работает во всех версиях РHP $associative = array('One' => 1, 'Two' => 2, 'Three' => 3); @@ -199,13 +200,13 @@ assert($c > $b); // больше assert($a <= $b); // меньше или равно assert($c >= $d); // больше или равно -// Следующие утверждения истинны если переменные имеют одинаковый тип. +// Следующие утверждения истинны, если переменные имеют одинаковый тип. assert($c === $d); assert($a !== $d); assert(1 == '1'); assert(1 !== '1'); -// Переменные могут изменять тип, в зависимости от их использования. +// Переменные могут изменять тип в зависимости от их использования. $integer = 1; echo $integer + $integer; // => 2 @@ -235,7 +236,7 @@ $var = null; // Null $integer = 10; $boolen = settype($integer, "string") // теперь $integer имеет строковый тип -// settype возвращает true - если преобразование удалось и false в противном случае +// settype возвращает true, если преобразование удалось и false в противном случае /******************************** * Управляющие структуры @@ -311,7 +312,7 @@ echo "\n"; for ($x = 0; $x < 10; $x++) { echo $x; -} // Prints "0123456789" +} // Напечатает "0123456789" echo "\n"; @@ -320,7 +321,7 @@ $wheels = ['bicycle' => 2, 'car' => 4]; // Циклы foreach могут обходить массивы foreach ($wheels as $wheel_count) { echo $wheel_count; -} // Prints "24" +} // Напечатает "24" echo "\n"; @@ -337,14 +338,14 @@ while ($i < 5) { break; // Exit out of the while loop } echo $i++; -} // Prints "012" +} // Напечатает "012" for ($i = 0; $i < 5; $i++) { if ($i === 3) { continue; // Skip this iteration of the loop } echo $i; -} // Prints "0124" +} // Напечатает "0124" /******************************** @@ -369,7 +370,7 @@ function add ($x, $y = 1) { // $y по умолчанию равно 1 echo add(4); // => 5 echo add(4, 2); // => 6 -// $result недоступна за пределами функции +// $result недоступен за пределами функции // print $result; // Выдает предупреждение // Начиная с PHP 5.3 вы можете объявлять анонимные функции: @@ -402,19 +403,19 @@ echo $function_name(1, 2); // => 3 /******************************** - * Includes + * Включения */ <?php // PHP код внутри включаемого файла должен начинаться с тега PHP. include 'my-file.php'; -// Код в файле my-file.php теперь доступен в текущем в текущем пространстве имен. -// Если файл не удалось включить, будет выдано предупреждение. +// Код в файле my-file.php теперь доступен в текущем пространстве имен. +// Если файл не удалось подключить, то будет выдано предупреждение. include_once 'my-file.php'; -// Если код в файле my-file.php уже был включен, он не будет включен повторно. -// Это предотвращает ошибку повторного включения файла. +// Если код в файле my-file.php уже был подключен, он не будет подключен повторно. +// Это предотвращает ошибку повторного подключения файла. require 'my-file.php'; require_once 'my-file.php'; @@ -422,7 +423,7 @@ require_once 'my-file.php'; // Same as include(), except require() will cause a fatal error if the // file cannot be included. // Действует также как и include(), но если файл не удалось подключить, -// функция выдает неисправимую ошибку +// функция выдает фатальную ошибку // Содержимое файла my-include.php: <?php @@ -452,19 +453,19 @@ class MyClass static $staticVar = 'static'; - // Properties must declare their visibility + // Свойства объявляются с указанием их видимости public $property = 'public'; public $instanceProp; - protected $prot = 'protected'; // Accessible from the class and subclasses - private $priv = 'private'; // Accessible within the class only + protected $prot = 'protected'; // Свойство доступно только потомкам и самому классу + private $priv = 'private'; // Свойство доступно только самому классу - // Create a constructor with __construct + // Конструктор описывается с помощью __construct public function __construct($instanceProp) { - // Access instance variables with $this + // Доступ к эземпляру класса с помощью $this $this->instanceProp = $instanceProp; } - // Methods are declared as functions inside a class + // Методы объявляются как функции принадлежащие классу public function myMethod() { print 'MyClass'; @@ -502,7 +503,7 @@ class MyOtherClass extends MyClass echo $this->prot; } - // Override a method + // Переопределение родительского метода function myMethod() { parent::myMethod(); @@ -595,7 +596,7 @@ class SomeOtherClass implements InterfaceOne, InterfaceTwo * Трейты */ -// Трейты появились в PHP 5.4.0 и объявляются при помощи ключевого слова trait +// Трейты появились в PHP 5.4 и объявляются при помощи ключевого слова trait trait MyTrait { @@ -611,7 +612,7 @@ class MyTraitfulClass } $cls = new MyTraitfulClass(); -$cls->myTraitMethod(); // Prints "I have MyTrait" +$cls->myTraitMethod(); // Напечатает "I have MyTrait" /******************************** diff --git a/ruby.html.markdown b/ruby.html.markdown index fe142365..0e798706 100644 --- a/ruby.html.markdown +++ b/ruby.html.markdown @@ -12,7 +12,7 @@ contributors: - ["Dzianis Dashkevich", "https://github.com/dskecse"] - ["Levi Bostian", "https://github.com/levibostian"] - ["Rahil Momin", "https://github.com/iamrahil"] - + - ["Gabriel Halley", https://github.com/ghalley"] --- ```ruby @@ -39,6 +39,7 @@ You shouldn't either 10 * 2 #=> 20 35 / 5 #=> 7 2**5 #=> 32 +5 % 3 #=> 2 # Arithmetic is just syntactic sugar # for calling a method on an object @@ -160,6 +161,7 @@ array = [1, 2, 3, 4, 5] #=> [1, 2, 3, 4, 5] # Arrays can be indexed # From the front array[0] #=> 1 +array.first #=> 1 array[12] #=> nil # Like arithmetic, [var] access @@ -170,6 +172,7 @@ array.[] 12 #=> nil # From the end array[-1] #=> 5 +array.last #=> 5 # With a start index and length array[2, 3] #=> [3, 4, 5] @@ -264,6 +267,12 @@ hash.each do |key, value| puts "#{key} is #{value}" end +# If you still need and index you can use "each_with_index" and define an index +# variable +array.each_with_index do |element, index| + puts "#{element} is number #{index} in the array" +end + counter = 1 while counter <= 5 do puts "iteration #{counter}" diff --git a/rust.html.markdown b/rust.html.markdown index b2854b0c..d0c56b4a 100644 --- a/rust.html.markdown +++ b/rust.html.markdown @@ -287,9 +287,9 @@ fn main() { // While a value is mutably borrowed, it cannot be accessed at all. let mut var2 = 4; let ref_var2: &mut i32 = &mut var2; - *ref_var2 += 2; + *ref_var2 += 2; // '*' is used to point to the mutably borrowed var2 - println!("{}", *ref_var2); // 6 + println!("{}", *ref_var2); // 6 , //var2 would not compile. //ref_var2 is of type &mut i32, so //stores a reference to an i32 not the value. // var2 = 2; // this would not compile because `var2` is borrowed } ``` diff --git a/tr-tr/objective-c-tr.html.markdown b/tr-tr/objective-c-tr.html.markdown index f27cbf08..727f973e 100644 --- a/tr-tr/objective-c-tr.html.markdown +++ b/tr-tr/objective-c-tr.html.markdown @@ -14,7 +14,7 @@ kendi çatıları olan Cocoa ve Cocoa Touch için kullanılan bir programlama di Genel açamlı, object-oriented bir yapıya sahip programlama dilidir. C programlama diline Smalltalk stilinde mesajlaşma ekler. -```objective_c +```objective-c // Tek satır yorum // işaretleri ile başlar /* diff --git a/vi-vn/objective-c-vi.html.markdown b/vi-vn/objective-c-vi.html.markdown index c97bb560..38e418e9 100644 --- a/vi-vn/objective-c-vi.html.markdown +++ b/vi-vn/objective-c-vi.html.markdown @@ -12,7 +12,7 @@ filename: LearnObjectiveC-vi.m Objective-C là ngôn ngữ lập trình chính được sử dụng bởi Apple cho các hệ điều hành OS X, iOS và các framework tương ứng của họ, Cocoa và Cocoa Touch.
Nó là một ngôn ngữ lập trình mục đích tổng quát, hướng đối tượng có bổ sung thêm kiểu truyền thông điệp giống Smalltalk vào ngôn ngữ lập trình C.
-```objective_c
+```objective-c
// Chú thích dòng đơn bắt đầu với //
/*
diff --git a/vi-vn/ruby-vi.html.markdown b/vi-vn/ruby-vi.html.markdown new file mode 100644 index 00000000..73382100 --- /dev/null +++ b/vi-vn/ruby-vi.html.markdown @@ -0,0 +1,549 @@ +--- +language: ruby +filename: learnruby.rb +contributors: + - ["David Underwood", "http://theflyingdeveloper.com"] + - ["Joel Walden", "http://joelwalden.net"] + - ["Luke Holder", "http://twitter.com/lukeholder"] + - ["Tristan Hume", "http://thume.ca/"] + - ["Nick LaMuro", "https://github.com/NickLaMuro"] + - ["Marcos Brizeno", "http://www.about.me/marcosbrizeno"] + - ["Ariel Krakowski", "http://www.learneroo.com"] + - ["Dzianis Dashkevich", "https://github.com/dskecse"] + - ["Levi Bostian", "https://github.com/levibostian"] + - ["Rahil Momin", "https://github.com/iamrahil"] + - ["Vinh Nguyen", "http://rubydaily.net"] +lang: vi-vn + +--- + +```ruby +# Đây là một comment + +=begin +Đây là một comment nhiều dòng +Không ai dùng cách này +Bạn không nên dùng +=end + +# Đầu tiên và quan trọng nhất: Mọi thứ là đối tượng. + +# Các con số là các đối tượng. + +3.class #=> Fixnum + +3.to_s #=> "3" + + +# Một vài bài toán số học căn bản +1 + 1 #=> 2 +8 - 1 #=> 7 +10 * 2 #=> 20 +35 / 5 #=> 7 +2**5 #=> 32 + +# Số học vừa là các cú pháp thân thiện cho việc gọi +# một hàm trên một đối tượng +1.+(3) #=> 4 +10.* 5 #=> 50 + +# Các giá trị đặc biệt là các đối tượng +nil # Ở đây không có gì để xem +true # luôn đúng +false # luôn sai + +nil.class #=> Lớp Nil +true.class #=> Lớp True +false.class #=> Lớp False + +# So sánh bằng +1 == 1 #=> true +2 == 1 #=> false + +# So sánh không bằng +1 != 1 #=> false +2 != 1 #=> true + +# Ngoài chính false, thì nil là một giá trị khác của false + +!nil #=> true +!false #=> true +!0 #=> false + +# Các loại so sánh khác +1 < 10 #=> true +1 > 10 #=> false +2 <= 2 #=> true +2 >= 2 #=> true + +# Các toán tử logic +true && false #=> false +true || false #=> true +!true #=> false + + +# Có các cách khác của các toán tử logic với mức thấp hơn +# Chúng được sử dụng như các cấu trúc điều khiển luồng nối các mệnh đề +# với nhau cho đến khi một trong số chúng trả về đúng hoặc sai. + +# `do_something_else` chỉ được gọi nếu như hàm `do_something` thành công. +do_something() and do_something_else() +# `log_error` chỉ được gọi nếu hàm `do_something` không thành công. +do_something() or log_error() + + +# Các chuỗi là các đối tượng + +'I am a string'.class #=> String +"I am a string too".class #=> String + +placeholder = 'use string interpolation' +"I can #{placeholder} when using double quoted strings" +#=> "I can use string interpolation when using double quoted strings" + +# Nên đưa các chuỗi vào trong dấu nháy đơn +# Ngoài ra dấu nháy kép được sử dụng trong tính toán. + +# Nối các chuỗi, nhưng không nối với các số. +'hello ' + 'world' #=> "hello world" +'hello ' + 3 #=> TypeError: can't convert Fixnum into String +'hello ' + 3.to_s #=> "hello 3" + +# Xuất ra ngoài màn hình +puts "I'm printing!" + +# Các biến +x = 25 #=> 25 +x #=> 25 + +# Chú ý về việc gán các giá trị được trả về vào biến. +# Điều này có nghĩa là bạn có thể gán nhiều biến. + +x = y = 10 #=> 10 +x #=> 10 +y #=> 10 + +# Theo quy ước, dùng snake_case cho các tên của biến. +snake_case = true + +# Dùng để mô tả tên các biến +path_to_project_root = '/good/name/' +path = '/bad/name/' + +# Ký tự (là các đối tượng) +# Các ký tự là bất biến, như các biến hằng số chỉ đến các số nguyên. +# Chúng thường xuyên được sử dụng thay cho các chuỗi để chuyển đổi các giá +# trị hiệu quả. + +:pending.class #=> Symbol + +status = :pending + +status == :pending #=> true + +status == 'pending' #=> false + +status == :approved #=> false + +# Các mảng + +# Đây là một mảng +array = [1, 2, 3, 4, 5] #=> [1, 2, 3, 4, 5] + +# Các mảng có thể chứa nhiều phần tử khác nhau + +[1, 'hello', false] #=> [1, "hello", false] + +# Có thể truy cập các giá trị của mảng thông qua các chỉ mục +array[0] #=> 1 +array[12] #=> nil + +# Giống như số học, sử dụng [biến] là một cú pháp thông dụng +array.[] 0 #=> 1 +array.[] 12 #=> nil + +# Lấy phần tử cuối cùng +array[-1] #=> 5 + +# Bắt đầu từ chỉ mục và số phần tử cần lấy +array[2, 3] #=> [3, 4, 5] + +# Đảo ngược một mảng +a=[1,2,3] +a.reverse! #=> [3,2,1] + +# Lấy một khoảng +array[1..3] #=> [2, 3, 4] + +# Thêm phần tử vào mảng bằng cách này +array << 6 #=> [1, 2, 3, 4, 5, 6] +# Hoặc cách này +array.push(6) #=> [1, 2, 3, 4, 5, 6] + +# Kiểm tra phần tử có tồn tại trong mảng +array.include?(1) #=> true + +# Băm là phần chính của Ruby với các cặp khoá/giá trị +# Băm được biểu thị bằng dấu ngoặc nhọn: +hash = { 'color' => 'green', 'number' => 5 } + +hash.keys #=> ['color', 'number'] + +# Băm có thể được truy cập nhanh chóng thông qua khoá +hash['color'] #=> 'green' +hash['number'] #=> 5 + +# Khoá không tồn tại sẽ trả về nil +hash['nothing here'] #=> nil + +# Kể từ Ruby bản 1.9, đây là một cú pháp đặc biệt, sử dụng symbol như khoá + +new_hash = { defcon: 3, action: true } + +new_hash.keys #=> [:defcon, :action] + +# Kiểm tra khoá hoặc giá trị có tồn tại hay không +new_hash.has_key?(:defcon) #=> true +new_hash.has_value?(3) #=> true + +# Mẹo: Cả Mảng và Băm đều là Enumberable +# Chúng cùng chia sẻ rất nhiều phương thức hữu ích như each, map, count... + +# Cấu trúc điều khiển + +if true + 'if statement' +elsif false + 'else if, optional' +else + 'else, also optional' +end + +for counter in 1..5 + puts "iteration #{counter}" +end +#=> iteration 1 +#=> iteration 2 +#=> iteration 3 +#=> iteration 4 +#=> iteration 5 + +# TUY NHIÊN, không ai sử dụng vòng lặp for. +# Thay vào đó, ban nên dùng phương thức "each" và truyền vào đó một khối. +# Một khối là một loạt các mã mà bạn có thể truyền +# cho một phương thức giống như each. +# Nó tương tự với lambda, các hàm ẩn danh hoặc closures trong các ngôn ngữ +# lập trình khác. +# +# Phương thức "each" cho một khoản sẽ chạy qua từng phần tử của khoảng đó. +# Khối được truyền vào là một số đếm như là tham số. +# Gọi một method "each" với một khối sẽ trông như thế này: + +(1..5).each do |counter| + puts "iteration #{counter}" +end +#=> iteration 1 +#=> iteration 2 +#=> iteration 3 +#=> iteration 4 +#=> iteration 5 + +# Bạn cũng có thể bao khối trong các dấu ngoặc nhọn. +(1..5).each { |counter| puts "iteration #{counter}" } + +# Các nội dung của cấu trúc dữ liệu cũng có thể được lặp bằng each. +array.each do |element| + puts "#{element} is part of the array" +end +hash.each do |key, value| + puts "#{key} is #{value}" +end + +counter = 1 +while counter <= 5 do + puts "iteration #{counter}" + counter += 1 +end +#=> iteration 1 +#=> iteration 2 +#=> iteration 3 +#=> iteration 4 +#=> iteration 5 + +grade = 'B' + +case grade +when 'A' + puts 'Way to go kiddo' +when 'B' + puts 'Better luck next time' +when 'C' + puts 'You can do better' +when 'D' + puts 'Scraping through' +when 'F' + puts 'You failed!' +else + puts 'Alternative grading system, eh?' +end +#=> "Better luck next time" + +# Cases cũng được dùng cho các dãy +grade = 82 +case grade +when 90..100 + puts 'Hooray!' +when 80...90 + puts 'OK job' +else + puts 'You failed!' +end +#=> "OK job" + +# Xử lý ngoại lệ: +begin + # Code ở đây có thể sẽ đưa ra một ngoại lệ. + raise NoMemoryError, 'You ran out of memory.' +rescue NoMemoryError => exception_variable + puts 'NoMemoryError was raised', exception_variable +rescue RuntimeError => other_exception_variable + puts 'RuntimeError was raised now' +else + puts 'This runs if no exceptions were thrown at all' +ensure + puts 'This code always runs no matter what' +end + +# Hàm + +def double(x) + x * 2 +end + +# Hàm (và tất cả các khối) được mặc định giá trị trả về ở mệnh đề cuối. +double(2) #=> 4 + +# Dấu ngoặc là một tuỳ chọn cho một kết quả rõ ràng. +double 3 #=> 6 + +double double 3 #=> 12 + +def sum(x, y) + x + y +end + +# Các đối số được chia cắt bởi dấu phẩy. +sum 3, 4 #=> 7 + +sum sum(3, 4), 5 #=> 12 + +# yield +# Tất cả các hàm có thể có một tham số tuỳ chọn. +# Nó có thể được gọi với từ khóa "yield". +def surround + puts '{' + yield + puts '}' +end + +surround { puts 'hello world' } + +# { +# hello world +# } + + +# Bạn có thể truyền một khối đến một hàm +# Dấu "&" được đánh dấu đến một khối +def guests(&block) + block.call 'some_argument' +end + +# Bạn có thể truyền một danh sách các tham số, nó sẽ được chuyển thành mảng. +# Thông qua việc sử dụng dấu *. +def guests(*array) + array.each { |guest| puts guest } +end + +# Định nghĩ một lớp thông qua từ khoá class. +class Human + + # Một biến class. Nó được chia sẽ cho tất cả các instance của lớp này. + @@species = 'H. sapiens' + + # Các khởi tạo căn bản + def initialize(name, age = 0) + # Gán đối số đến biến instance "name" + @name = name + # Nếu không có age, sẽ lấy giá trị mặc định trong danh sách đối số. + @age = age + end + + # Hàm nhập giá trị căn bản + def name=(name) + @name = name + end + + # Hàm lấy giá trị căn bản + def name + @name + end + + # Các hàm trên có thể được gọn lại bằng cách dùng hàm attr_accessor + attr_accessor :name + + # Các hàm nhận/lấy cũng có thể được tạo riêng như sau: + attr_reader :name + attr_writer :name + + # Một hàm lớp dùng self để phân biệt với hàm instance. + # Nó chỉ có thể được gọi trên lớp. + def self.say(msg) + puts msg + end + + def species + @@species + end +end + + +# Khởi tạo một lớp +jim = Human.new('Jim Halpert') + +dwight = Human.new('Dwight K. Schrute') + +# Hãy gọi một cặp các hàm. +jim.species #=> "H. sapiens" +jim.name #=> "Jim Halpert" +jim.name = "Jim Halpert II" #=> "Jim Halpert II" +jim.name #=> "Jim Halpert II" +dwight.species #=> "H. sapiens" +dwight.name #=> "Dwight K. Schrute" + +# Gọi một hàm lớp +Human.say('Hi') #=> "Hi" + +# Phạm vi của biến được định nghĩa bởi cách chúng ta đặt tên cho chúng. +# Các biến bắt đầu với dấu $ là biến toàn cục. +$var = "I'm a global var" +defined? $var #=> "global-variable" + +# Các biến bắt đầu với dấu @ là biến phạm vi. +@var = "I'm an instance var" +defined? @var #=> "instance-variable" + +# Các biến bắt đầu với dấu @@ có pham vi là trong một lớp. +@@var = "I'm a class var" +defined? @@var #=> "class variable" + +# Các biến bắt đầu với ký tự viết hoa là biến hằng. +Var = "I'm a constant" +defined? Var #=> "constant" + +# Lớp cũng là một đối tượng trong Ruby. Bởi vậy lớp có các biến instance. +# Biến lớp được chia sẽ trong lớp và các lớp kế thừa nó. + +# Lớp cơ sở +class Human + @@foo = 0 + + def self.foo + @@foo + end + + def self.foo=(value) + @@foo = value + end +end + +# Lớp kế thừa +class Worker < Human +end + +Human.foo # 0 +Worker.foo # 0 + +Human.foo = 2 # 2 +Worker.foo # 2 + +# Các biến lớp instance không được chia sẽ trong lớp kế thừa. + +class Human + @bar = 0 + + def self.bar + @bar + end + + def self.bar=(value) + @bar = value + end +end + +class Doctor < Human +end + +Human.bar # 0 +Doctor.bar # nil + +module ModuleExample + def foo + 'foo' + end +end + +# Include một module sẽ đưa các hàm của module thành instances của lớp. +# Extend một module sẽ đưa các hàm của module thành các biến của lớp. + +class Person + include ModuleExample +end + +class Book + extend ModuleExample +end + +Person.foo # => NoMethodError: undefined method `foo' for Person:Class +Person.new.foo # => 'foo' +Book.foo # => 'foo' +Book.new.foo # => NoMethodError: undefined method `foo' + +# Hàm hồi quy được thực hiện khi include và extend một module. + +module ConcernExample + def self.included(base) + base.extend(ClassMethods) + base.send(:include, InstanceMethods) + end + + module ClassMethods + def bar + 'bar' + end + end + + module InstanceMethods + def qux + 'qux' + end + end +end + +class Something + include ConcernExample +end + +Something.bar # => 'bar' +Something.qux # => NoMethodError: undefined method `qux' +Something.new.bar # => NoMethodError: undefined method `bar' +Something.new.qux # => 'qux' +``` + +## Các nguồn tham khảo thêm. + +- [Learn Ruby by Example with Challenges](http://www.learneroo.com/modules/61/nodes/338) - A variant of this reference with in-browser challenges. +- [Official Documentation](http://www.ruby-doc.org/core-2.1.1/) +- [Ruby from other languages](https://www.ruby-lang.org/en/documentation/ruby-from-other-languages/) +- [Programming Ruby](http://www.amazon.com/Programming-Ruby-1-9-2-0-Programmers/dp/1937785491/) - An older [free edition](http://ruby-doc.com/docs/ProgrammingRuby/) is available online. +- [Ruby Style Guide](https://github.com/bbatsov/ruby-style-guide) - A community-driven Ruby coding style guide. diff --git a/xml.html.markdown b/xml.html.markdown index 4d33e614..547deb08 100644 --- a/xml.html.markdown +++ b/xml.html.markdown @@ -83,7 +83,7 @@ With this tool, you can check the XML data outside the application logic. <!DOCTYPE note SYSTEM "Bookstore.dtd"> <bookstore> <book category="COOKING"> - <title >Everyday Italian</title> + <title>Everyday Italian</title> <price>30.00</price> </book> </bookstore> @@ -121,7 +121,7 @@ With this tool, you can check the XML data outside the application logic. <bookstore> <book category="COOKING"> - <title >Everyday Italian</title> + <title>Everyday Italian</title> <price>30.00</price> </book> </bookstore> |