Steven, According to the current Python source the default value of maxsplit=-1. I think you can count on that as I don't think there would be a reason to change it in the future. If you are really worried about it then your version of calling a particular version of split should work.
By the way, if you use Python 2.5 and when your maxsplit function is called there is a clear common case in regards to maxsplit, you could use the new conditional expression. Say most of the time mysplit is used with a default value of maxsplit, then you can re-write your 'if' code as --------------------- result=S.split(sep) if maxsplit is None else S.split(sep,maxsplit) --------------------- -Nick Vatamaniuc Steven D'Aprano wrote: > I'm having problems passing a default value to the maxsplit argument of > str.split. I'm trying to write a function which acts as a wrapper to > split, something like this: > > def mysplit(S, sep=None, maxsplit=None): > pre_processing() > result = S.split(sep, maxsplit) > post_processing() > return result > > But the split method doesn't accept a value of None for maxsplit, and I > don't know what default value I should be using. Passing 0 as the default > isn't correct, because then it splits zero times. > > By experimentation, I have discovered that passing -1 as the default > instead of None *appears* to work, but I'm not sure if I can rely on it or > if that is an accidental implementation detail. According to the > documentation at > http://docs.python.org/lib/string-methods.html#string-methods > > split([sep [,maxsplit]]) > Return a list of the words in the string, using sep as the delimiter > string. If maxsplit is given, at most maxsplit splits are done. (thus, > the list will have at most maxsplit+1 elements). If maxsplit is not > specified, then there is no limit on the number of splits (all > possible splits are made). > > > If I take that literally, then the correct way to wrap split is something > like this: > > def mysplit(S, sep=None, maxsplit=None): > pre_processing() > if maxsplit is None: > # don't specify maxsplit > result = S.split(sep) > else: > result = S.split(sep, maxsplit) > post_processing() > return result > > Is it safe for me to pass -1 as the default to maxsplit, meaning > "unlimited splits"? Should the docs be fixed to mention that? > > Thanks, > > > > -- > Steven. -- http://mail.python.org/mailman/listinfo/python-list
