[].sort() should return self

[dwt]

BPO	13805
Nosy	@ezio-melotti

^{Note: these values reflect the state of the issue at the time it was migrated and might not reflect the current state.}

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GitHub fields:

assignee = None
closed_at = <Date 2012-01-17.10:24:35.967>
created_at = <Date 2012-01-17.10:21:51.405>
labels = ['type-feature']
title = '[].sort() should return self'
updated_at = <Date 2012-01-17.10:28:59.399>
user = 'https://bugs.python.org/dwt'

bugs.python.org fields:

activity = <Date 2012-01-17.10:28:59.399>
actor = 'ezio.melotti'
assignee = 'none'
closed = True
closed_date = <Date 2012-01-17.10:24:35.967>
closer = 'ezio.melotti'
components = []
creation = <Date 2012-01-17.10:21:51.405>
creator = 'dwt'
dependencies = []
files = []
hgrepos = []
issue_num = 13805
keywords = []
message_count = 4.0
messages = ['151439', '151440', '151441', '151442']
nosy_count = 2.0
nosy_names = ['ezio.melotti', 'dwt']
pr_nums = []
priority = 'normal'
resolution = 'rejected'
stage = 'resolved'
status = 'closed'
superseder = None
type = 'enhancement'
url = 'https://bugs.python.org/issue13805'
versions = ['Python 2.7']

[dwt]

[].sort() returns None which means you can't chain it.

So for example someDict.keys().sort()[0] doesn't work but you have to use sorted(someDict.keys())[0] instead which is harder to read as you have to read the line not from the beginning to the end but jump back and forth in it to understand it (which gets progressively harder as the individual parts of it get longer / more complex).

[dwt]

It really should return self.

[ezio-melotti]

This is by design.
Methods that mutate the object return None.
Methods that create a new object return the new object.
list.sort sorts the list in place, so it returns None.

[ezio-melotti]

See also http://docs.python.org/faq/design.html#why-doesn-t-list-sort-return-the-sorted-list