Bugs item #811604, was opened at 2003-09-24 04:20 Message generated for change (Comment added) made by mondragon You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=105470&aid=811604&group_id=5470

Category: Python Interpreter Core Group: None

Priority: 5 Submitted By: T.Meyarivan (meyarivan) Assigned to: Nobody/Anonymous (nobody) Summary: "string".split behaviour for empty strings

Initial Comment:

"".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.

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Date: 2004-03-21 12:11

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Fixed in doc/lib/libstring.tex version 1.57

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Comment By: Terry J. Reedy (tjreedy) Date: 2003-09-28 19:50

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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.

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Comment By: T.Meyarivan (meyarivan) Date: 2003-09-26 07:04

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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..

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Comment By: Raymond Hettinger (rhettinger) Date: 2003-09-26 00:35

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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"

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Comment By: T.Meyarivan (meyarivan) Date: 2003-09-24 04:51

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"".split(None) -> []

which is expected because in the case when no sep is specified and when sep == None, split_whitespace is called..

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