Issue 811604: "string".split behaviour for empty strings (original) (raw)

This issue has been migrated to GitHub: https://github.com/python/cpython/issues/39287

classification

process

Created on 2003-09-24 08:20 by meyarivan, last changed 2022-04-10 16:11 by admin. This issue is now closed.

Messages (6)
msg18312 - (view)	Author: T.Meyarivan (meyarivan)	Date: 2003-09-24 08:20
"".split() -> [] "".split(' ') -> [''] It is not clear from the documentation as to what is the defined behaviour in the above case. To say the least, it is completely counter-intuitive..(splitting an empty string should return the list [''] in both cases). From stringobject.c, the behaviour of split_whitespace (i.e split called without sep) and string_split (split called with sep) is different for empty strings..perhaps the function split_whitespace needs to be patched.
msg18313 - (view)	Author: T.Meyarivan (meyarivan)	Date: 2003-09-24 08:51
Logged In: YES user_id=30470 "".split(None) -> [] which is expected because in the case when no sep is specified and when sep == None, split_whitespace is called..
msg18314 - (view)	Author: Raymond Hettinger (rhettinger) *	Date: 2003-09-26 04:35
Logged In: YES user_id=80475 And so it is. The whitespace version (no args) and the specified separator version work differently -- the second version can never return an empty list. This code has been around for a good while and it is likely that much code relies on the behavior, so I recommend classifying it as a beauty spot and closing the bug. "One man's bug is another man's feature"
msg18315 - (view)	Author: T.Meyarivan (meyarivan)	Date: 2003-09-26 11:04
Logged In: YES user_id=30470 Thats so counter intuitive.. :-( At least the documentation should specify the fact that the behaviour of "string".split for empty strings is so and so.... The reason this probably never came up ( or mostly ignored by majority ) is that people probably check if the string is empty before proceeding to process it.. I am not closing the bug before the specific behaviour of "string".split for empty strings gets to the docs..
msg18316 - (view)	Author: Terry J. Reedy (terry.reedy) *	Date: 2003-09-28 23:50
Logged In: YES user_id=593130 Suggestion: find section of Lib Ref discussing str.split, quote existing def, and add succinct sentence that you think is needed. Then change category to 'documentation' so appropriate person(s) will see proposal.
msg18317 - (view)	Author: Nick Bastin (nbastin) *	Date: 2004-03-21 17:11
Logged In: YES user_id=430343 Fixed in doc/lib/libstring.tex version 1.57