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Fix some inconsistencies so that the doc can be read top to bottom
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@ -87,6 +87,8 @@ not False #=> True
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# A newer way to format strings is the format method.
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# This method is the preferred way
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"{0} can be {1}".format("strings", "formatted")
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# You can use keywords if you don't want to count.
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"{name} wants to eat {food}".format(name="Bob", food="lasagna")
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# None is an object
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None #=> None
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@ -104,16 +106,12 @@ print "I'm Python. Nice to meet you!"
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some_var = 5 # Convention is to use lower_case_with_underscores
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some_var #=> 5
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# Accessing a previously unassigned variable is an exception
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try:
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some_other_var
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except NameError:
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print "Raises a name error"
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# Accessing a previously unassigned variable is an exception.
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# See Control Flow to learn more about exception handling.
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some_other_var # Raises a name error
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# if can be used as an expression
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some_var = 1 if 1 > 2 else 2 # => 2
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# If a is greater than b, then a is assigned to some_var.
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# Otherwise b is assigned to some_var.
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"yahoo!" if 1 > 2 else 2 #=> "yahoo!"
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# Lists store sequences
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li = []
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@ -136,10 +134,7 @@ li[0] #=> 1
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li[-1] #=> 3
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# Looking out of bounds is an IndexError
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try:
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li[4] # Raises an IndexError
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except IndexError:
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print "Raises an IndexError"
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li[4] # Raises an IndexError
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# You can look at ranges with slice syntax.
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# (It's a closed/open range for you mathy types.)
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@ -167,10 +162,7 @@ len(li) #=> 6
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# Tuples are like lists but are immutable.
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tup = (1, 2, 3)
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tup[0] #=> 1
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try:
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tup[0] = 3 # Raises a TypeError
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except TypeError:
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print "Tuples cannot be mutated."
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tup[0] = 3 # Raises a TypeError
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# You can do all those list thingies on tuples too
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len(tup) #=> 3
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@ -207,16 +199,12 @@ filled_dict.values() #=> [3, 2, 1]
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"one" in filled_dict #=> True
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1 in filled_dict #=> False
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try:
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# Trying to look up a non-existing key will raise a KeyError
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filled_dict["four"] #=> KeyError
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except KeyError:
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pass
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# Looking up a non-existing key is a KeyError
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filled_dict["four"] # KeyError
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# Use get method to avoid the KeyError
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filled_dict.get("one") #=> 1
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filled_dict.get("four") #=> None
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# The get method supports a default argument when the value is missing
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filled_dict.get("one", 4) #=> 1
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filled_dict.get("four", 4) #=> 4
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@ -259,7 +247,7 @@ filled_set | other_set #=> {1, 2, 3, 4, 5, 6}
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# Let's just make a variable
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some_var = 5
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# Here is an if statement. INDENTATION IS SIGNIFICANT IN PYTHON!
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# Here is an if statement. Indentation is significant in python!
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# prints "some var is smaller than 10"
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if some_var > 10:
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print "some_var is totally bigger than 10."
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@ -340,21 +328,22 @@ def keyword_args(**kwargs):
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keyword_args(big="foot", loch="ness") #=> {"big": "foot", "loch": "ness"}
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# You can do both at once, if you like
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def foo(*args, **kwargs):
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def all_the_args(*args, **kwargs):
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print args
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print kwargs
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"""
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all_the_args(1, 2, a=3, b=4) prints:
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[1, 2]
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(1, 2)
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{"a": 3, "b": 4}
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"""
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# You can also use * and ** when calling a function
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# When calling functions, you can do the opposite of varargs/kwargs!
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# Use * to expand tuples and use ** to expand kwargs.
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args = (1, 2, 3, 4)
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kwargs = {"a": 3, "b": 4}
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foo(*args) # equivalent to foo(1, 2, 3, 4)
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foo(**kwargs) # equivalent to foo(a=3, b=4)
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foo(*args, **kwargs) # equivalent to foo(1, 2, 3, 4, a=3, b=4)
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all_the_args(*args) # equivalent to foo(1, 2, 3, 4)
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all_the_args(**kwargs) # equivalent to foo(a=3, b=4)
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all_the_args(*args, **kwargs) # equivalent to foo(1, 2, 3, 4, a=3, b=4)
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# Python has first class functions
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def create_adder(x):
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