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Diffstat (limited to 'python.html.markdown')
| -rw-r--r-- | python.html.markdown | 68 |
1 files changed, 39 insertions, 29 deletions
diff --git a/python.html.markdown b/python.html.markdown index 53381f32..ace3f794 100644 --- a/python.html.markdown +++ b/python.html.markdown @@ -14,7 +14,7 @@ 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. +to Python 2.x. For Python 3.x, take a look at the [Python 3 tutorial](http://learnxinyminutes.com/docs/python3/). ```python @@ -46,7 +46,7 @@ to Python 2.x. For Python 3.x, take a look at the Python 3 tutorial. 2.0 # This is a float 11.0 / 4.0 # => 2.75 ahhh...much better -# Result of integer division truncated down both for positive and negative. +# 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 @@ -101,6 +101,8 @@ not False # => True # Strings can be added too! "Hello " + "world!" # => "Hello world!" +# Strings can be added without using '+' +"Hello " "world!" # => "Hello world!" # ... or multiplied "Hello" * 3 # => "HelloHelloHello" @@ -139,12 +141,8 @@ bool("") # => False ## 2. Variables and Collections #################################################### -# Python has a print statement, in all 2.x versions but removed from 3. +# Python has a print statement print "I'm Python. Nice to meet you!" -# Python also has a print function, available in versions 2.7 and 3... -# but for 2.7 you need to add the import (uncommented): -# from __future__ import print_function -print("I'm also Python! ") # No need to declare variables before assigning to them. some_var = 5 # Convention is to use lower_case_with_underscores @@ -193,14 +191,14 @@ li[2:] # => [4, 3] li[:3] # => [1, 2, 4] # Select every second entry li[::2] # =>[1, 4] -# Revert the list +# Reverse a copy of the list li[::-1] # => [3, 4, 2, 1] # Use any combination of these to make advanced slices # li[start:end:step] # Remove arbitrary elements from a list with "del" del li[2] # li is now [1, 2, 3] - +r # You can add lists li + other_li # => [1, 2, 3, 4, 5, 6] # Note: values for li and for other_li are not modified. @@ -264,7 +262,7 @@ 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 -# note that filled_dict.get("four") is still => 4 +# note that filled_dict.get("four") is still => None # (get doesn't set the value in the dictionary) # set the value of a key with a syntax similar to lists @@ -314,11 +312,11 @@ some_var = 5 # Here is an if statement. Indentation is significant in python! # prints "some_var is smaller than 10" if some_var > 10: - print("some_var is totally bigger than 10.") + print "some_var is totally bigger than 10." elif some_var < 10: # This elif clause is optional. - print("some_var is smaller than 10.") + print "some_var is smaller than 10." else: # This is optional too. - print("some_var is indeed 10.") + print "some_var is indeed 10." """ @@ -330,7 +328,7 @@ prints: """ for animal in ["dog", "cat", "mouse"]: # You can use % to interpolate formatted strings - print("%s is a mammal" % animal) + print "%s is a mammal" % animal """ "range(number)" returns a list of numbers @@ -342,7 +340,19 @@ prints: 3 """ for i in range(4): - print(i) + print i + +""" +"range(lower, upper)" returns a list of numbers +from the lower number to the upper number +prints: + 4 + 5 + 6 + 7 +""" +for i in range(4, 8): + print i """ While loops go until a condition is no longer met. @@ -354,7 +364,7 @@ prints: """ x = 0 while x < 4: - print(x) + print x x += 1 # Shorthand for x = x + 1 # Handle exceptions with a try/except block @@ -377,7 +387,7 @@ else: # Optional clause to the try/except block. Must follow all except blocks # Use "def" to create new functions def add(x, y): - print("x is %s and y is %s" % (x, y)) + print "x is %s and y is %s" % (x, y) return x + y # Return values with a return statement # Calling functions with parameters @@ -406,8 +416,8 @@ keyword_args(big="foot", loch="ness") # => {"big": "foot", "loch": "ness"} # You can do both at once, if you like def all_the_args(*args, **kwargs): - print(args) - print(kwargs) + print args + print kwargs """ all_the_args(1, 2, a=3, b=4) prints: (1, 2) @@ -429,14 +439,14 @@ def pass_all_the_args(*args, **kwargs): print varargs(*args) print keyword_args(**kwargs) -# Function Scope +# Function Scope x = 5 def setX(num): # Local var x not the same as global variable x x = num # => 43 print x # => 43 - + def setGlobalX(num): global x print x # => 5 @@ -503,10 +513,10 @@ class Human(object): # Instantiate a class i = Human(name="Ian") -print(i.say("hi")) # prints out "Ian: hi" +print i.say("hi") # prints out "Ian: hi" j = Human("Joel") -print(j.say("hello")) # prints out "Joel: hello" +print j.say("hello") # prints out "Joel: hello" # Call our class method i.get_species() # => "H. sapiens" @@ -526,12 +536,12 @@ Human.grunt() # => "*grunt*" # You can import modules import math -print(math.sqrt(16)) # => 4 +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 @@ -577,7 +587,7 @@ xrange_ = xrange(1, 900000000) # will double all numbers until a result >=30 found for i in double_numbers(xrange_): - print(i) + print i if i >= 30: break @@ -606,8 +616,8 @@ def say(say_please=False): return msg, say_please -print(say()) # Can you buy me a beer? -print(say(say_please=True)) # Can you buy me a beer? Please! I am poor :( +print say() # Can you buy me a beer? +print say(say_please=True) # Can you buy me a beer? Please! I am poor :( ``` ## Ready For More? |