def keyword_arguments(**keywords):
return sorted(keywords.keys())
if __name__ == '__main__':
print keyword_arguments(arg1 = 1, arg2 = 2, arg3 = 3)
the above code returns ['arg1', 'arg2', 'arg3'] correctly. However, if I replace the return statement in the function like so:
return keywords.keys().sort()
it returns None. Why is this?
This is because sort() returns None. It just sorts the list in place. You should do:
return sorted(keywords.keys())
a = [2,3,1]
>>> print a.sort()
None
>>> print a
[1, 2, 3]
a = keywords.keys()
a.sort()
return a
keywords and leave out a
return a will still return None in that example
keyword.keys(), you are getting the dictionary keys as a separate list, Then you would sort them and then they just get discarded. You still end up returning the unordered dictionary keys because the next time you do keyword.keys() for returning them, it takes them from the dictionary again.
sortreturnsNone.