From 77672e78916c4d35a67934b6c78e20b015ec687a Mon Sep 17 00:00:00 2001 From: ldinh Date: Sun, 30 Jun 2013 15:16:55 -0700 Subject: [PATCH] Fix some inconsistencies so that the doc can be read top to bottom --- python.html.markdown | 47 +++++++++++++++++--------------------------- 1 file changed, 18 insertions(+), 29 deletions(-) diff --git a/python.html.markdown b/python.html.markdown index 467a179e..9b0f0241 100644 --- a/python.html.markdown +++ b/python.html.markdown @@ -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):