Fix some inconsistencies so that the doc can be read top to bottom

This commit is contained in:
ldinh 2013-06-30 15:16:55 -07:00
parent 329eba20a5
commit 77672e7891

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