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-rw-r--r--README.markdown5
-rw-r--r--git.html.markdown5
-rw-r--r--haskell.html.markdown2
-rw-r--r--python.html.markdown2
-rw-r--r--r.html.markdown315
-rw-r--r--ruby.html.markdown60
-rw-r--r--scala.html.markdown6
-rw-r--r--zh-cn/dart-cn.html.markdown498
8 files changed, 790 insertions, 103 deletions
diff --git a/README.markdown b/README.markdown
index 77e09abd..efc2fa07 100644
--- a/README.markdown
+++ b/README.markdown
@@ -16,8 +16,9 @@ properly!
The most requested languages are:
-* Scala
-* Javascript
+* Go
+* ~~Scala~~
+* ~~Javascript~~
... but there are many more requests to do "every language", so don't let that stop you.
diff --git a/git.html.markdown b/git.html.markdown
index 00f38d60..d8537300 100644
--- a/git.html.markdown
+++ b/git.html.markdown
@@ -310,7 +310,12 @@ Pulls from a repository and merges it with another branch.
# Update your local repo, by merging in new changes
# from the remote "origin" and "master" branch.
# git pull <remote> <branch>
+# git pull => implicitly defaults to => git pull origin master
$ git pull origin master
+
+# Merge in changes from remote branch and rebase
+# branch commits onto your local repo, like: "git pull <remote> <branch>, git rebase <branch>"
+$ git pull origin master --rebase
```
### push
diff --git a/haskell.html.markdown b/haskell.html.markdown
index be7d8669..9847ef2a 100644
--- a/haskell.html.markdown
+++ b/haskell.html.markdown
@@ -131,7 +131,7 @@ add 1 2 -- 3
-- with backticks:
1 `add` 2 -- 3
--- You can also define functions that have no characters! This lets
+-- You can also define functions that have no letters! This lets
-- you define your own operators! Here's an operator that does
-- integer division
(//) a b = a `div` b
diff --git a/python.html.markdown b/python.html.markdown
index a32db51a..f0b74d08 100644
--- a/python.html.markdown
+++ b/python.html.markdown
@@ -6,7 +6,7 @@ filename: learnpython.py
---
Python was created by Guido Van Rossum in the early 90's. It is now one of the most popular
-languages in existence. I fell in love with Python for its syntactic clarity. Its basically
+languages in existence. I fell in love with Python for its syntactic clarity. It's basically
executable pseudocode.
Feedback would be highly appreciated! You can reach me at [@louiedinh](http://twitter.com/louiedinh) or louiedinh [at] [google's email service]
diff --git a/r.html.markdown b/r.html.markdown
index 0240e8fb..dd94072b 100644
--- a/r.html.markdown
+++ b/r.html.markdown
@@ -5,7 +5,7 @@ contributors:
filename: learnr.r
---
-R is a statistical computing language. It has lots of good built-in functions for uploading and cleaning data sets, running common statistical tests, and making graphs. You can also easily compile it within a LaTeX document.
+R is a statistical computing language. It has lots of libraries for uploading and cleaning data sets, running statistical procedures, and making graphs. You can also run `R`commands within a LaTeX document.
```python
@@ -14,63 +14,244 @@ R is a statistical computing language. It has lots of good built-in functions fo
# You can't make a multi-line comment per se,
# but you can stack multiple comments like so.
-# Hit COMMAND-ENTER to execute a line
+# in Windows, hit COMMAND-ENTER to execute a line
+
+
+###################################################################
+# Stuff you can do without understanding anything about programming
+###################################################################
+
+data() # Browse pre-loaded data sets
+data(rivers) # Lengths of Major North American Rivers
+ls() # Notice that "rivers" appears in the workspace
+head(rivers) # peek at the dataset
+# 735 320 325 392 524 450
+length(rivers) # how many rivers were measured?
+# 141
+summary(rivers)
+# Min. 1st Qu. Median Mean 3rd Qu. Max.
+# 135.0 310.0 425.0 591.2 680.0 3710.0
+stem(rivers) #stem-and-leaf plot (like a histogram)
+#
+# The decimal point is 2 digit(s) to the right of the |
+#
+# 0 | 4
+# 2 | 011223334555566667778888899900001111223333344455555666688888999
+# 4 | 111222333445566779001233344567
+# 6 | 000112233578012234468
+# 8 | 045790018
+# 10 | 04507
+# 12 | 1471
+# 14 | 56
+# 16 | 7
+# 18 | 9
+# 20 |
+# 22 | 25
+# 24 | 3
+# 26 |
+# 28 |
+# 30 |
+# 32 |
+# 34 |
+# 36 | 1
+
+
+stem(log(rivers)) #Notice that the data are neither normal nor log-normal! Take that, Bell Curve fundamentalists.
+
+# The decimal point is 1 digit(s) to the left of the |
+#
+# 48 | 1
+# 50 |
+# 52 | 15578
+# 54 | 44571222466689
+# 56 | 023334677000124455789
+# 58 | 00122366666999933445777
+# 60 | 122445567800133459
+# 62 | 112666799035
+# 64 | 00011334581257889
+# 66 | 003683579
+# 68 | 0019156
+# 70 | 079357
+# 72 | 89
+# 74 | 84
+# 76 | 56
+# 78 | 4
+# 80 |
+# 82 | 2
+
+
+hist(rivers, col="#333333", border="white", breaks=25) #play around with these parameters
+hist(log(rivers), col="#333333", border="white", breaks=25) #you'll do more plotting later
+
+#Here's another neat data set that comes pre-loaded. R has tons of these. data()
+data(discoveries)
+plot(discoveries, col="#333333", lwd=3, xlab="Year", main="Number of important discoveries per year")
+plot(discoveries, col="#333333", lwd=3, type = "h", xlab="Year", main="Number of important discoveries per year")
+
+
+#rather than leaving the default ordering (by year) we could also sort to see what's typical
+sort(discoveries)
+# [1] 0 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1 1 1 1 1 2 2 2 2
+# [26] 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 3 3 3
+# [51] 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 4 4 4 4 4 4 4 4
+# [76] 4 4 4 4 5 5 5 5 5 5 5 6 6 6 6 6 6 7 7 7 7 8 9 10 12
+
+stem(discoveries, scale=2)
+#
+# The decimal point is at the |
+#
+# 0 | 000000000
+# 1 | 000000000000
+# 2 | 00000000000000000000000000
+# 3 | 00000000000000000000
+# 4 | 000000000000
+# 5 | 0000000
+# 6 | 000000
+# 7 | 0000
+# 8 | 0
+# 9 | 0
+# 10 | 0
+# 11 |
+# 12 | 0
+
+max(discoveries)
+# 12
+
+summary(discoveries)
+# Min. 1st Qu. Median Mean 3rd Qu. Max.
+# 0.0 2.0 3.0 3.1 4.0 12.0
+
+
+
+
+#Basic statistical operations don't require any programming knowledge either
+
+#roll a die a few times
+round(runif(7, min=.5, max=6.5))
+# 1 4 6 1 4 6 4
+
+#your numbers will differ from mine unless we set the same random.seed(31337)
+
+
+#draw from a standard Gaussian 9 times
+rnorm(9)
+# [1] 0.07528471 1.03499859 1.34809556 -0.82356087 0.61638975 -1.88757271
+# [7] -0.59975593 0.57629164 1.08455362
+
+
+
+
+
+
+
+
#########################
-# The absolute basics
+# Basic programming stuff
#########################
# NUMBERS
-# We've got doubles! Behold the "numeric" class
-5 # => [1] 5
-class(5) # => [1] "numeric"
-# We've also got integers! They look suspiciously similar,
-# but indeed are different
-5L # => [1] 5
-class(5L) # => [1] "integer"
+# "numeric" means double-precision floating-point numbers
+5 # 5
+class(5) # "numeric"
+5e4 # 50000 #handy when dealing with large,small,or variable orders of magnitude
+6.02e23 # Avogadro's number
+1.6e-35 # Planck length
+
+# long-storage integers are written with L
+5L # 5
+class(5L) # "integer"
+
# Try ?class for more information on the class() function
-# In fact, you can look up the documentation on just about anything with ?
+# In fact, you can look up the documentation on `xyz` with ?xyz
+# or see the source for `xyz` by evaluating xyz
+
+# Arithmetic
+10 + 66 # 76
+53.2 - 4 # 49.2
+2 * 2.0 # 4
+3L / 4 # 0.75
+3 %% 2 # 1
+
+# Weird number types
+class(NaN) # "numeric"
+class(Inf) # "numeric"
+class(-Inf) # "numeric" #used in for example integrate( dnorm(x), 3, Inf ) -- which obviates Z-score tables
+
+# but beware, NaN isn't the only weird type...
+class(NA) # see below
+class(NULL) # NULL
+
+
+# SIMPLE LISTS
+c(6, 8, 7, 5, 3, 0, 9) # 6 8 7 5 3 0 9
+c('alef', 'bet', 'gimmel', 'dalet', 'he') # "alef" "bet" "gimmel" "dalet" "he"
+c('Z', 'o', 'r', 'o') == "Zoro" # FALSE FALSE FALSE FALSE
+
+#some more nice built-ins
+5:15 # 5 6 7 8 9 10 11 12 13 14 15
+
+seq(from=0, to=31337, by=1337)
+# [1] 0 1337 2674 4011 5348 6685 8022 9359 10696 12033 13370 14707
+# [13] 16044 17381 18718 20055 21392 22729 24066 25403 26740 28077 29414 30751
+
+letters
+# [1] "a" "b" "c" "d" "e" "f" "g" "h" "i" "j" "k" "l" "m" "n" "o" "p" "q" "r" "s"
+# [20] "t" "u" "v" "w" "x" "y" "z"
+
+month.abb # "Jan" "Feb" "Mar" "Apr" "May" "Jun" "Jul" "Aug" "Sep" "Oct" "Nov" "Dec"
+
+
+# Access the n'th element of a list with list.name[n] or sometimes list.name[[n]]
+letters[18] # "r"
+LETTERS[13] # "M"
+month.name[9] # "September"
+c(6, 8, 7, 5, 3, 0, 9)[3] # 7
-# All the normal operations!
-10 + 66 # => [1] 76
-53.2 - 4 # => [1] 49.2
-2 * 2.0 # => [1] 4
-3L / 4 # => [1] 0.75
-3 %% 2 # => [1] 1
-# Finally, we've got not-a-numbers! They're numerics too
-class(NaN) # => [1] "numeric"
# CHARACTERS
-# We've (sort of) got strings! Behold the "character" class
-"plugh" # => [1] "plugh"
-class("plugh") # "character"
# There's no difference between strings and characters in R
+"Horatio" # "Horatio"
+class("Horatio") # "character"
+substr("Fortuna multis dat nimis, nulli satis.", 9, 15) # "multis "
+gsub('u', 'ø', "Fortuna multis dat nimis, nulli satis.") # "Fortøna møltis dat nimis, nølli satis."
+
+
+
# LOGICALS
-# We've got booleans! Behold the "logical" class
-class(TRUE) # => [1] "logical"
-class(FALSE) # => [1] "logical"
+# booleans
+class(TRUE) # "logical"
+class(FALSE) # "logical"
# Behavior is normal
-TRUE == TRUE # => [1] TRUE
-TRUE == FALSE # => [1] FALSE
-FALSE != FALSE # => [1] FALSE
-FALSE != TRUE # => [1] TRUE
+TRUE == TRUE # TRUE
+TRUE == FALSE # FALSE
+FALSE != FALSE # FALSE
+FALSE != TRUE # TRUE
# Missing data (NA) is logical, too
-class(NA) # => [1] "logical"
+class(NA) # "logical"
+
+
# FACTORS
# The factor class is for categorical data
-# It has an attribute called levels that describes all the possible categories
-factor("dog")
-# =>
-# [1] dog
-# Levels: dog
-# (This will make more sense once we start talking about vectors)
+# which can be ordered (like childrens' grade levels)
+# or unordered (like gender)
+levels(factor(c("female", "male", "male", "female", "NA", "female"))) # "female" "male" "NA"
+
+factor(c("female", "female", "male", "NA", "female"))
+# female female male NA female
+# Levels: female male NA
+
+data(infert) #Infertility after Spontaneous and Induced Abortion
+levels(infert$education) # "0-5yrs" "6-11yrs" "12+ yrs"
+
+
# VARIABLES
@@ -80,8 +261,8 @@ y <- "1" # this is preferred
TRUE -> z # this works but is weird
# We can use coerce variables to different classes
-as.numeric(y) # => [1] 1
-as.character(x) # => [1] "5"
+as.numeric(y) # 1
+as.character(x) # "5"
# LOOPS
@@ -122,7 +303,7 @@ myFunc <- function(x) {
}
# Called like any other R function:
-myFunc(5) # => [1] 19
+myFunc(5) # 19
#########################
# Fun with data: vectors, matrices, data frames, and arrays
@@ -132,35 +313,35 @@ myFunc(5) # => [1] 19
# You can vectorize anything, so long as all components have the same type
vec <- c(8, 9, 10, 11)
-vec # => [1] 8 9 10 11
+vec # 8 9 10 11
# The class of a vector is the class of its components
-class(vec) # => [1] "numeric"
+class(vec) # "numeric"
# If you vectorize items of different classes, weird coercions happen
-c(TRUE, 4) # => [1] 1 4
-c("dog", TRUE, 4) # => [1] "dog" "TRUE" "4"
+c(TRUE, 4) # 1 4
+c("dog", TRUE, 4) # "dog" "TRUE" "4"
# We ask for specific components like so (R starts counting from 1)
-vec[1] # => [1] 8
+vec[1] # 8
# We can also search for the indices of specific components,
-which(vec %% 2 == 0) # => [1] 1 3
+which(vec %% 2 == 0) # 1 3
# or grab just the first or last entry in the vector
-head(vec, 1) # => [1] 8
-tail(vec, 1) # => [1] 11
+head(vec, 1) # 8
+tail(vec, 1) # 11
# If an index "goes over" you'll get NA:
-vec[6] # => [1] NA
+vec[6] # NA
# You can find the length of your vector with length()
-length(vec) # => [1] 4
+length(vec) # 4
# You can perform operations on entire vectors or subsets of vectors
-vec * 4 # => [1] 16 20 24 28
-vec[2:3] * 5 # => [1] 25 30
+vec * 4 # 16 20 24 28
+vec[2:3] * 5 # 25 30
# and there are many built-in functions to summarize vectors
-mean(vec) # => [1] 9.5
-var(vec) # => [1] 1.666667
-sd(vec) # => [1] 1.290994
-max(vec) # => [1] 11
-min(vec) # => [1] 8
-sum(vec) # => [1] 38
+mean(vec) # 9.5
+var(vec) # 1.666667
+sd(vec) # 1.290994
+max(vec) # 11
+min(vec) # 8
+sum(vec) # 38
# TWO-DIMENSIONAL (ALL ONE CLASS)
@@ -175,11 +356,11 @@ mat
# Unlike a vector, the class of a matrix is "matrix", no matter what's in it
class(mat) # => "matrix"
# Ask for the first row
-mat[1,] # => [1] 1 4
+mat[1,] # 1 4
# Perform operation on the first column
-3 * mat[,1] # => [1] 3 6 9
+3 * mat[,1] # 3 6 9
# Ask for a specific cell
-mat[3,2] # => [1] 6
+mat[3,2] # 6
# Transpose the whole matrix
t(mat)
# =>
@@ -196,7 +377,7 @@ mat2
# [2,] "2" "cat"
# [3,] "3" "bird"
# [4,] "4" "dog"
-class(mat2) # => [1] matrix
+class(mat2) # matrix
# Again, note what happened!
# Because matrices must contain entries all of the same class,
# everything got converted to the character class
@@ -216,7 +397,7 @@ mat3
# For columns of different classes, use the data frame
dat <- data.frame(c(5,2,1,4), c("dog", "cat", "bird", "dog"))
names(dat) <- c("number", "species") # name the columns
-class(dat) # => [1] "data.frame"
+class(dat) # "data.frame"
dat
# =>
# number species
@@ -224,14 +405,14 @@ dat
# 2 2 cat
# 3 1 bird
# 4 4 dog
-class(dat$number) # => [1] "numeric"
-class(dat[,2]) # => [1] "factor"
+class(dat$number) # "numeric"
+class(dat[,2]) # "factor"
# The data.frame() function converts character vectors to factor vectors
# There are many twisty ways to subset data frames, all subtly unalike
-dat$number # => [1] 5 2 1 4
-dat[,1] # => [1] 5 2 1 4
-dat[,"number"] # => [1] 5 2 1 4
+dat$number # 5 2 1 4
+dat[,1] # 5 2 1 4
+dat[,"number"] # 5 2 1 4
# MULTI-DIMENSIONAL (ALL OF ONE CLASS)
diff --git a/ruby.html.markdown b/ruby.html.markdown
index 99817982..861a94ad 100644
--- a/ruby.html.markdown
+++ b/ruby.html.markdown
@@ -275,36 +275,36 @@ surround { puts 'hello world' }
# Define a class with the class keyword
class Human
- # A class variable. It is shared by all instances of this class.
- @@species = "H. sapiens"
-
- # Basic initializer
- def initialize(name, age=0)
- # Assign the argument to the "name" instance variable for the instance
- @name = name
- # If no age given, we will fall back to the default in the arguments list.
- @age = age
- end
-
- # Basic setter method
- def name=(name)
- @name = name
- end
-
- # Basic getter method
- def name
- @name
- end
-
- # A class method uses self to distinguish from instance methods.
- # It can only be called on the class, not an instance.
- def self.say(msg)
- puts "#{msg}"
- end
-
- def species
- @@species
- end
+ # A class variable. It is shared by all instances of this class.
+ @@species = "H. sapiens"
+
+ # Basic initializer
+ def initialize(name, age=0)
+ # Assign the argument to the "name" instance variable for the instance
+ @name = name
+ # If no age given, we will fall back to the default in the arguments list.
+ @age = age
+ end
+
+ # Basic setter method
+ def name=(name)
+ @name = name
+ end
+
+ # Basic getter method
+ def name
+ @name
+ end
+
+ # A class method uses self to distinguish from instance methods.
+ # It can only be called on the class, not an instance.
+ def self.say(msg)
+ puts "#{msg}"
+ end
+
+ def species
+ @@species
+ end
end
diff --git a/scala.html.markdown b/scala.html.markdown
index fef09404..b1b3ecbf 100644
--- a/scala.html.markdown
+++ b/scala.html.markdown
@@ -408,9 +408,11 @@ for(line <- Source.fromPath("myfile.txt").getLines())
[Scala for the impatient](http://horstmann.com/scala/)
-[Twitter Scala school(http://twitter.github.io/scala_school/)
+[Twitter Scala school](http://twitter.github.io/scala_school/)
-[The scala documentation]
+[The scala documentation](http://docs.scala-lang.org/)
+
+[Try Scala in your browser](http://scalatutorials.com/tour/)
Join the [Scala user group](https://groups.google.com/forum/#!forum/scala-user)
diff --git a/zh-cn/dart-cn.html.markdown b/zh-cn/dart-cn.html.markdown
new file mode 100644
index 00000000..64663b21
--- /dev/null
+++ b/zh-cn/dart-cn.html.markdown
@@ -0,0 +1,498 @@
+---
+language: dart
+filename: learndart.dart
+contributors:
+ - ["Joao Pedrosa", "https://github.com/jpedrosa/"]
+translators:
+ - ["Guokai Han", "https://github.com/hanguokai/"]
+---
+
+Dart 是编程语言王国的新人。
+它借鉴了许多其他主流语言,并且不会偏离它的兄弟语言 JavaScript 太多。
+就像 JavaScript 一样,Dart 的目标是提供良好的浏览器集成。
+
+Dart 最有争议的特性必然是它的可选类型。
+
+```javascript
+import "dart:collection";
+import "dart:math" as DM;
+
+// 欢迎进入15分钟的 Dart 学习。 http://www.dartlang.org/
+// 这是一个可实际执行的向导。你可以用 Dart 运行它
+// 或者在线执行! 可以把代码复制/粘贴到这个网站。 http://try.dartlang.org/
+
+// 函数声明和方法声明看起来一样。
+// 函数声明可以嵌套。声明使用这种 name() {} 的形式,
+// 或者 name() => 单行表达式; 的形式。
+// 右箭头的声明形式会隐式地返回表达式的结果。
+example1() {
+ example1nested1() {
+ example1nested2() => print("Example1 nested 1 nested 2");
+ example1nested2();
+ }
+ example1nested1();
+}
+
+// 匿名函数没有函数名。
+example2() {
+ example2nested1(fn) {
+ fn();
+ }
+ example2nested1(() => print("Example2 nested 1"));
+}
+
+// 当声明函数类型的参数的时候,声明中可以包含
+// 函数参数需要的参数,指定所需的参数名即可。
+example3() {
+ example3nested1(fn(informSomething)) {
+ fn("Example3 nested 1");
+ }
+ example3planB(fn) { // 或者不声明函数参数的参数
+ fn("Example3 plan B");
+ }
+ example3nested1((s) => print(s));
+ example3planB((s) => print(s));
+}
+
+// 函数有可以访问到外层变量的闭包。
+var example4Something = "Example4 nested 1";
+example4() {
+ example4nested1(fn(informSomething)) {
+ fn(example4Something);
+ }
+ example4nested1((s) => print(s));
+}
+
+// 下面这个包含 sayIt 方法的类声明,同样有一个可以访问外层变量的闭包,
+// 就像前面的函数一样。
+var example5method = "Example5 sayIt";
+class Example5Class {
+ sayIt() {
+ print(example5method);
+ }
+}
+example5() {
+ // 创建一个 Example5Class 类的匿名实例,
+ // 并调用它的 sayIt 方法。
+ new Example5Class().sayIt();
+}
+
+// 类的声明使用这种形式 class name { [classBody] }.
+// classBody 中可以包含实例方法和变量,
+// 还可以包含类方法和变量。
+class Example6Class {
+ var example6InstanceVariable = "Example6 instance variable";
+ sayIt() {
+ print(example6InstanceVariable);
+ }
+}
+example6() {
+ new Example6Class().sayIt();
+}
+
+// 类方法和变量使用 static 关键词声明。
+class Example7Class {
+ static var example7ClassVariable = "Example7 class variable";
+ static sayItFromClass() {
+ print(example7ClassVariable);
+ }
+ sayItFromInstance() {
+ print(example7ClassVariable);
+ }
+}
+example7() {
+ Example7Class.sayItFromClass();
+ new Example7Class().sayItFromInstance();
+}
+
+// 字面量非常方便,但是对于在函数/方法的外层的字面量有一个限制,
+// 类的外层或外面的字面量必需是常量。
+// 字符串和数字默认是常量。
+// 但是 array 和 map 不是。他们需要用 "const" 声明为常量。
+var example8A = const ["Example8 const array"],
+ example8M = const {"someKey": "Example8 const map"};
+example8() {
+ print(example8A[0]);
+ print(example8M["someKey"]);
+}
+
+// Dart 中的循环使用标准的 for () {} 或 while () {} 的形式,
+// 以及更加现代的 for (.. in ..) {} 的形式, 或者
+// 以 forEach 开头并具有许多特性支持的函数回调的形式。
+var example9A = const ["a", "b"];
+example9() {
+ for (var i = 0; i < example9A.length; i++) {
+ print("Example9 for loop '${example9A[i]}'");
+ }
+ var i = 0;
+ while (i < example9A.length) {
+ print("Example9 while loop '${example9A[i]}'");
+ i++;
+ }
+ for (var e in example9A) {
+ print("Example9 for-in loop '${e}'");
+ }
+ example9A.forEach((e) => print("Example9 forEach loop '${e}'"));
+}
+
+// 遍历字符串中的每个字符或者提取其子串。
+var example10S = "ab";
+example10() {
+ for (var i = 0; i < example10S.length; i++) {
+ print("Example10 String character loop '${example10S[i]}'");
+ }
+ for (var i = 0; i < example10S.length; i++) {
+ print("Example10 substring loop '${example10S.substring(i, i + 1)}'");
+ }
+}
+
+// 支持两种数字格式 int 和 double 。
+example11() {
+ var i = 1 + 320, d = 3.2 + 0.01;
+ print("Example11 int ${i}");
+ print("Example11 double ${d}");
+}
+
+// DateTime 提供了日期/时间的算法。
+example12() {
+ var now = new DateTime.now();
+ print("Example12 now '${now}'");
+ now = now.add(new Duration(days: 1));
+ print("Example12 tomorrow '${now}'");
+}
+
+// 支持正则表达式。
+example13() {
+ var s1 = "some string", s2 = "some", re = new RegExp("^s.+?g\$");
+ match(s) {
+ if (re.hasMatch(s)) {
+ print("Example13 regexp matches '${s}'");
+ } else {
+ print("Example13 regexp doesn't match '${s}'");
+ }
+ }
+ match(s1);
+ match(s2);
+}
+
+// 布尔表达式必需被解析为 true 或 false,
+// 因为不支持隐式转换。
+example14() {
+ var v = true;
+ if (v) {
+ print("Example14 value is true");
+ }
+ v = null;
+ try {
+ if (v) {
+ // 不会执行
+ } else {
+ // 不会执行
+ }
+ } catch (e) {
+ print("Example14 null value causes an exception: '${e}'");
+ }
+}
+
+// try/catch/finally 和 throw 语句用于异常处理。
+// throw 语句可以使用任何对象作为参数。
+example15() {
+ try {
+ try {
+ throw "Some unexpected error.";
+ } catch (e) {
+ print("Example15 an exception: '${e}'");
+ throw e; // Re-throw
+ }
+ } catch (e) {
+ print("Example15 catch exception being re-thrown: '${e}'");
+ } finally {
+ print("Example15 Still run finally");
+ }
+}
+
+// 要想有效地动态创建长字符串,
+// 应该使用 StringBuffer。 或者 join 一个字符串的数组。
+example16() {
+ var sb = new StringBuffer(), a = ["a", "b", "c", "d"], e;
+ for (e in a) { sb.write(e); }
+ print("Example16 dynamic string created with "
+ "StringBuffer '${sb.toString()}'");
+ print("Example16 join string array '${a.join()}'");
+}
+
+// 字符串连接只需让相邻的字符串字面量挨着,
+// 不需要额外的操作符。
+example17() {
+ print("Example17 "
+ "concatenate "
+ "strings "
+ "just like that");
+}
+
+// 字符串使用单引号或双引号做分隔符,二者并没有实际的差异。
+// 这种灵活性可以很好地避免内容中需要转义分隔符的情况。
+// 例如,字符串内容里的 HTML 属性使用了双引号。
+example18() {
+ print('Example18 <a href="etc">'
+ "Don't can't I'm Etc"
+ '</a>');
+}
+
+// 用三个单引号或三个双引号表示的字符串
+// 可以跨越多行,并且包含行分隔符。
+example19() {
+ print('''Example19 <a href="etc">
+Example19 Don't can't I'm Etc
+Example19 </a>''');
+}
+
+// 字符串可以使用 $ 字符插入内容。
+// 使用 $ { [expression] } 的形式,表达式的值会被插入到字符串中。
+// $ 跟着一个变量名会插入变量的值。
+// 如果要在字符串中插入 $ ,可以使用 \$ 的转义形式代替。
+example20() {
+ var s1 = "'\${s}'", s2 = "'\$s'";
+ print("Example20 \$ interpolation ${s1} or $s2 works.");
+}
+
+// 可选类型允许作为 API 的标注,并且可以辅助 IDE,
+// 这样 IDE 可以更好地提供重构、自动完成和错误检测功能。
+// 目前为止我们还没有声明任何类型,并且程序运行地很好。
+// 事实上,类型在运行时会被忽略。
+// 类型甚至可以是错的,并且程序依然可以执行,
+// 好像和类型完全无关一样。
+// 有一个运行时参数可以让程序进入检查模式,它会在运行时检查类型错误。
+// 这在开发时很有用,但是由于增加了额外的检查会使程序变慢,
+// 因此应该避免在部署时使用。
+class Example21 {
+ List<String> _names;
+ Example21() {
+ _names = ["a", "b"];
+ }
+ List<String> get names => _names;
+ set names(List<String> list) {
+ _names = list;
+ }
+ int get length => _names.length;
+ void add(String name) {
+ _names.add(name);
+ }
+}
+void example21() {
+ Example21 o = new Example21();
+ o.add("c");
+ print("Example21 names '${o.names}' and length '${o.length}'");
+ o.names = ["d", "e"];
+ print("Example21 names '${o.names}' and length '${o.length}'");
+}
+
+// 类的继承形式是 class name extends AnotherClassName {} 。
+class Example22A {
+ var _name = "Some Name!";
+ get name => _name;
+}
+class Example22B extends Example22A {}
+example22() {
+ var o = new Example22B();
+ print("Example22 class inheritance '${o.name}'");
+}
+
+// 类也可以使用 mixin 的形式 :
+// class name extends SomeClass with AnotherClassName {}.
+// 必需继承某个类才能 mixin 另一个类。
+// 当前 mixin 的模板类不能有构造函数。
+// Mixin 主要是用来和辅助的类共享方法的,
+// 这样单一继承就不会影响代码复用。
+// Mixin 声明在类定义的 "with" 关键词后面。
+class Example23A {}
+class Example23Utils {
+ addTwo(n1, n2) {
+ return n1 + n2;
+ }
+}
+class Example23B extends Example23A with Example23Utils {
+ addThree(n1, n2, n3) {
+ return addTwo(n1, n2) + n3;
+ }
+}
+example23() {
+ var o = new Example23B(), r1 = o.addThree(1, 2, 3),
+ r2 = o.addTwo(1, 2);
+ print("Example23 addThree(1, 2, 3) results in '${r1}'");
+ print("Example23 addTwo(1, 2) results in '${r2}'");
+}
+
+// 类的构造函数名和类名相同,形式为
+// SomeClass() : super() {}, 其中 ": super()" 的部分是可选的,
+// 它用来传递参数给父类的构造函数。
+class Example24A {
+ var _value;
+ Example24A({value: "someValue"}) {
+ _value = value;
+ }
+ get value => _value;
+}
+class Example24B extends Example24A {
+ Example24B({value: "someOtherValue"}) : super(value: value);
+}
+example24() {
+ var o1 = new Example24B(),
+ o2 = new Example24B(value: "evenMore");
+ print("Example24 calling super during constructor '${o1.value}'");
+ print("Example24 calling super during constructor '${o2.value}'");
+}
+
+// 对于简单的类,有一种设置构造函数参数的快捷方式。
+// 只需要使用 this.parameterName 的前缀,
+// 它就会把参数设置为同名的实例变量。
+class Example25 {
+ var value, anotherValue;
+ Example25({this.value, this.anotherValue});
+}
+example25() {
+ var o = new Example25(value: "a", anotherValue: "b");
+ print("Example25 shortcut for constructor '${o.value}' and "
+ "'${o.anotherValue}'");
+}
+
+// 可以在大括号 {} 中声明命名参数。
+// 大括号 {} 中声明的参数的顺序是随意的。
+// 在中括号 [] 中声明的参数也是可选的。
+example26() {
+ var _name, _surname, _email;
+ setConfig1({name, surname}) {
+ _name = name;
+ _surname = surname;
+ }
+ setConfig2(name, [surname, email]) {
+ _name = name;
+ _surname = surname;
+ _email = email;
+ }
+ setConfig1(surname: "Doe", name: "John");
+ print("Example26 name '${_name}', surname '${_surname}', "
+ "email '${_email}'");
+ setConfig2("Mary", "Jane");
+ print("Example26 name '${_name}', surname '${_surname}', "
+ "email '${_email}'");
+}
+
+// 使用 final 声明的变量只能被设置一次。
+// 在类里面,final 实例变量可以通过常量的构造函数参数设置。
+class Example27 {
+ final color1, color2;
+ // 更灵活一点的方法是在冒号 : 后面设置 final 实例变量。
+ Example27({this.color1, color2}) : color2 = color2;
+}
+example27() {
+ final color = "orange", o = new Example27(color1: "lilac", color2: "white");
+ print("Example27 color is '${color}'");
+ print("Example27 color is '${o.color1}' and '${o.color2}'");
+}
+
+// 要导入一个库,使用 import "libraryPath" 的形式,或者如果要导入的是
+// 核心库使用 import "dart:libraryName" 。还有一个称为 "pub" 的包管理工具,
+// 它使用 import "package:packageName" 的约定形式。
+// 看下这个文件顶部的 import "dart:collection"; 语句。
+// 导入语句必需在其它代码声明之前出现。IterableBase 来自于 dart:collection 。
+class Example28 extends IterableBase {
+ var names;
+ Example28() {
+ names = ["a", "b"];
+ }
+ get iterator => names.iterator;
+}
+example28() {
+ var o = new Example28();
+ o.forEach((name) => print("Example28 '${name}'"));
+}
+
+// 对于控制流语句,我们有:
+// * 必需带 break 的标准 switch 语句
+// * if-else 和三元操作符 ..?..:..
+// * 闭包和匿名函数
+// * break, continue 和 return 语句
+example29() {
+ var v = true ? 30 : 60;
+ switch (v) {
+ case 30:
+ print("Example29 switch statement");
+ break;
+ }
+ if (v < 30) {
+ } else if (v > 30) {
+ } else {
+ print("Example29 if-else statement");
+ }
+ callItForMe(fn()) {
+ return fn();
+ }
+ rand() {
+ v = new DM.Random().nextInt(50);
+ return v;
+ }
+ while (true) {
+ print("Example29 callItForMe(rand) '${callItForMe(rand)}'");
+ if (v != 30) {
+ break;
+ } else {
+ continue;
+ }
+ // 不会到这里。
+ }
+}
+
+// 解析 int,把 double 转成 int,或者使用 ~/ 操作符在除法计算时仅保留整数位。
+// 让我们也来场猜数游戏吧。
+example30() {
+ var gn, tooHigh = false,
+ n, n2 = (2.0).toInt(), top = int.parse("123") ~/ n2, bottom = 0;
+ top = top ~/ 6;
+ gn = new DM.Random().nextInt(top + 1); // +1 because nextInt top is exclusive
+ print("Example30 Guess a number between 0 and ${top}");
+ guessNumber(i) {
+ if (n == gn) {
+ print("Example30 Guessed right! The number is ${gn}");
+ } else {
+ tooHigh = n > gn;
+ print("Example30 Number ${n} is too "
+ "${tooHigh ? 'high' : 'low'}. Try again");
+ }
+ return n == gn;
+ }
+ n = (top - bottom) ~/ 2;
+ while (!guessNumber(n)) {
+ if (tooHigh) {
+ top = n - 1;
+ } else {
+ bottom = n + 1;
+ }
+ n = bottom + ((top - bottom) ~/ 2);
+ }
+}
+
+// 程序的唯一入口点是 main 函数。
+// 在程序开始执行 main 函数之前,不期望执行任何外层代码。
+// 这样可以帮助程序更快地加载,甚至仅惰性加载程序启动时需要的部分。
+main() {
+ print("Learn Dart in 15 minutes!");
+ [example1, example2, example3, example4, example5, example6, example7,
+ example8, example9, example10, example11, example12, example13, example14,
+ example15, example16, example17, example18, example19, example20,
+ example21, example22, example23, example24, example25, example26,
+ example27, example28, example29, example30
+ ].forEach((ef) => ef());
+}
+
+```
+
+## 延伸阅读
+
+Dart 有一个综合性网站。它涵盖了 API 参考、入门向导、文章以及更多,
+还包括一个有用的在线试用 Dart 页面。
+http://www.dartlang.org/
+http://try.dartlang.org/
+
+
+