The following example shows the error I am getting when trying to use a string function inside a function call to map. I need help with why this happening. Thanks.
>>> s=["this is a string","python python python","split split split"]
>>> map(split,s)
Traceback (most recent call last):
File "<pyshell#16>", line 1, in <module>
map(split,s)
NameError: name 'split' is not defined
though split() is an in-built function, but it still throws this error?
It will work fine if you use str.split()
I.e,
s = ["this is a string","python python python","split split split"]
map(str.split, s)
gives:
[['this', 'is', 'a', 'string'],
['python', 'python', 'python'],
['split', 'split', 'split']]
The error message states: NameError: name 'split' is not defined, so the interpreter doesn't recognize split because split is not a built-in function. In order for this to work you have to associate split with the built-in str object.
Update: Wording improved based on @Ivc's helpful comments/suggestions.
'blah'.split('a') is equivalent to str.split('blah', 'a'), same as instanceofmyclass.mymethod(arg) is equivalent to MyClass.mymethod(instanceofmyclass, arg) - the string is the self argument to str.split.
map(lambda x: x.split(), s), or better, just go [x.split() for x in s]
split to a string it's usually clear which split we mean.split is not a built-in function, though str.split is a method of a built-in object. Generally, you would call split as a method of a str object, so that's why it's bound directly.
Check the output from the interpreter:
>>> str
<type 'str'>
>>> str.split
<method 'split' of 'str' objects>
