[New-bugs-announce] [issue21620] OrderedDict KeysView set operations not supported

[Matthew Lauria]

New submission from Matthew Lauria:

I noticed that doing set operations on an OrderedDict KeysView only works when the KeysView is the first input to the expression, and not when it's the second input. This is not the case for dicts.

Python 3.4.1 (default, May 31 2014, 11:25:02) 
[GCC 4.8.2] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import collections
>>> x = collections.OrderedDict()
>>> x.keys() - set()
set()
>>> set() - x.keys()
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: unsupported operand type(s) for -: 'set' and 'KeysView'

>>> y = {}
>>> y.keys() - set()
set()
>>> set() - y.keys()
set()

----------
components: Library (Lib)
messages: 219454
nosy: Matthew.Lauria, rhettinger
priority: normal
severity: normal
status: open
title: OrderedDict KeysView set operations not supported
type: behavior
versions: Python 3.4

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Python tracker <report at bugs.python.org>
<http://bugs.python.org/issue21620>
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