classification
Title: itertools.permutations docstring is misleading
Type: behavior Stage:
Components: Library (Lib) Versions: Python 2.6
process
Status: closed Resolution: fixed
Dependencies: Superseder:
Assigned To: Nosy List: ajaksu2, georg.brandl, rhettinger
Priority: normal Keywords:

Created on 2008-04-02 10:48 by ajaksu2, last changed 2008-06-10 12:48 by georg.brandl. This issue is now closed.

Messages (2)
msg64846 - (view) Author: Daniel Diniz (ajaksu2) * (Python triager) Date: 2008-04-02 10:48
Currently, Modules/itertoolsmodule.c lines 2471-2475 are:

PyDoc_STRVAR(permutations_doc,
"permutations(iterables[, r]) --> permutations object\n\
\n\
Return successive r-length permutations of elements in the iterable.\n\n\
permutations(range(4), 3) --> (0,1,2), (0,1,3), (0,2,3), (1,2,3)");

but that describes  behavior of itertools.combinations. The correct
example is in a comment on line 2254 of the same file:

'permutations(range(3), 2) --> (0,1) (0,2) (1,0) (1,2) (2,0) (2,1)'


I used "misleading" instead of "wrong" because the current docstring
does show a subset of the real output and could be said to be
incomplete. If that is the case, I suggest being explicit:

'permutations(range(4), 3) --> (0, 1, 2), (0, 1, 3), (0, 2, 1), (0, 2,
3), (0, 3, 1), (0, 3, 2), (1, 0, 2), (1, 0, 3), (1, 2, 0), (1, 2, 3),
(1, 3, 0), (1, 3, 2), (2, 0, 1), (2, 0, 3), (2, 1, 0), (2, 1, 3), (2, 3,
0), (2, 3, 1), (3, 0, 1), (3, 0, 2), (3, 1, 0), (3, 1, 2), (3, 2, 0),
(3, 2, 1)'
msg67902 - (view) Author: Georg Brandl (georg.brandl) * (Python committer) Date: 2008-06-10 12:48
Fixed in r64067.
History
Date User Action Args
2008-06-10 12:48:35georg.brandlsetstatus: open -> closed
resolution: fixed
messages: + msg67902
nosy: + georg.brandl
2008-04-02 10:48:02ajaksu2create