From cc3dc30518605f80e2ef11751a050ebd2997bac9 Mon Sep 17 00:00:00 2001
From: Michael Lee <michael.lee.0x2a@gmail.com>
Date: Sat, 29 Jun 2013 21:35:11 -0700
Subject: Added a few lines about truthiness, how lists can contain arbitrary
 data types, how you can unpack both tuples and lists, using 
ange, assigning
 lambdas to variables, dictionary comprehensions,  modules, and links to more
 info about the standard library.

---
 python.html.markdown | 66 ++++++++++++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 64 insertions(+), 2 deletions(-)

(limited to 'python.html.markdown')

diff --git a/python.html.markdown b/python.html.markdown
index 19e2aebe..c75e90c4 100644
--- a/python.html.markdown
+++ b/python.html.markdown
@@ -93,6 +93,16 @@ not False #=> True
 # None is an object
 None #=> None
 
+# Don't use the equality `==` symbol to compare objects to None
+# Use `is` instead
+"etc" is None #=> False
+None is None  #=> True
+
+# None, 0, and empty strings/lists all evaluate to False.
+# All other values are True
+0 == False  #=> True
+"" == False #=> True
+
 
 ####################################################
 ## 2. Variables and Collections
@@ -159,6 +169,9 @@ li.extend(other_li) # Now li is [1, 2, 3, 4, 5, 6]
 # Examine the length with len
 len(li) #=> 6
 
+# Note: lists can contain arbitrary values
+li2 = [1, "Hello", [[], "Hi", 5,]]
+
 # Tuples are like lists but are immutable.
 tup = (1, 2, 3)
 tup[0] #=> 1
@@ -170,7 +183,7 @@ tup + (4, 5, 6) #=> (1, 2, 3, 4, 5, 6)
 tup[:2] #=> (1, 2)
 2 in tup #=> True
 
-# You can unpack tuples into variables
+# 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
 # Tuples are created by default if you leave out the parentheses
 d, e, f = 4, 5, 6
@@ -267,6 +280,18 @@ prints:
 for animal in ["dog", "cat", "mouse"]:
     # You can use % to interpolate formatted strings
     print "%s is a mammal" % animal
+    
+"""
+`range(number)` returns a list of numbers 
+from zero to the given number
+prints:
+    0
+    1
+    2
+    3
+"""
+for i in range(4):
+    print i
 
 """
 While loops go until a condition is no longer met.
@@ -350,6 +375,8 @@ add_10(3) #=> 13
 
 # There are also anonymous functions
 (lambda x: x > 2)(3) #=> True
+rectangle_area = lambda a, b: a * b
+print rectangle_area(3, 4) #=> 12
 
 # There are built-in higher order functions
 map(add_10, [1,2,3]) #=> [11, 12, 13]
@@ -359,6 +386,9 @@ filter(lambda x: x > 5, [3, 4, 5, 6, 7]) #=> [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]
 
+# You can also use dictionary comprehensions
+{i: add_10(i) for i in [1, 2, 3]} #=> {1: 11, 2: 12, 3: 13}
+
 ####################################################
 ## 5. Classes
 ####################################################
@@ -374,7 +404,8 @@ class Human(object):
         # Assign the argument to the instance's name attribute
         self.name = name
 
-    # An instance method. All methods take self as the first argument
+    # An instance method. All methods take self as the first argument,
+    # which refers to the instance of this class
     def say(self, msg):
        return "%s: %s" % (self.name, msg)
 
@@ -407,6 +438,33 @@ j.get_species() #=> "H. neanderthalensis"
 
 # Call the static method
 Human.grunt() #=> "*grunt*"
+
+
+####################################################
+## 6. Modules
+####################################################
+
+# You can import modules
+import math
+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 floor3.7) #=> 3.0
+
+# You can import all functions from a module.
+# Warning: this is not recommended
+from math import *
+
+# You can shorten module names
+import math as m
+math.sqrt(16) == m.sqrt(16) #=> True
+
+# Python modules are just ordinary python files. You
+# can write your own, and import them.
+
+
 ```
 
 ## Further Reading
@@ -417,3 +475,7 @@ Still up for more? Try:
 * [Dive Into Python](http://www.diveintopython.net/)
 * [The Official Docs](http://docs.python.org/2.6/)
 * [Hitchhiker's Guide to Python](http://docs.python-guide.org/en/latest/)
+
+Python has a huge amount of modules within the standard library. See the 
+[official documentation](http://docs.python.org/2/library/index.html) or
+[Python Module of the Week](http://pymotw.com/2/) for more.
-- 
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