[issue14828] itertools.groupby not working as expected
Jiba
report at bugs.python.org
Wed May 16 11:51:34 CEST 2012
New submission from Jiba <jibalamy at free.fr>:
In some situation, itertools.groupby fails to group the objects, and produces several groups with the same key. For example, the following code :
from itertools import *
class P(object):
def __init__(self, key):
self.key = key
p1 = P(1)
p2 = P(2)
p3 = P(1)
for key, ps in groupby([p1, p2, p3], lambda p: p.key):
print "group", key
for p in ps:
print " - object", p
Produces the following result :
group 1
- object <__main__.P object at 0xb73d6acc>
group 2
- object <__main__.P object at 0xb73d6aec>
group 1
- object <__main__.P object at 0xb73d6b0c>
While I would expect to have only a single group 1, e.g. something like :
group 1
- object <__main__.P object at 0xb73d6acc>
- object <__main__.P object at 0xb73d6b0c>
group 2
- object <__main__.P object at 0xb73d6aec>
It seems that this bug also affects Python 3 (tested on Python 3.1.2)
----------
components: Library (Lib)
messages: 160822
nosy: Jiba
priority: normal
severity: normal
status: open
title: itertools.groupby not working as expected
type: behavior
versions: Python 2.7
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Python tracker <report at bugs.python.org>
<http://bugs.python.org/issue14828>
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