New submission from Tadhg McDonald-Jensen:
Currently the string representation for dictionary views are a bit misleading
as they look like valid expression but isn't:
>>> {'a':1, 'b':2}.keys()
dict_keys(['b', 'a'])
>>> dict_keys = type({}.keys()) #get a reference to the type
>>> dict_keys(['b', 'a'])
Traceback (most recent call last):
File "<pyshell#24>", line 1, in <module>
dict_keys(['b', 'a'])
TypeError: cannot create 'dict_keys' instances
This seems inconsistent with the documentation for 'repr'
https://docs.python.org/3/reference/datamodel.html#object.__repr__
"If at all possible, this should look like a valid Python expression that could
be used to recreate an object with the same value (given an appropriate
environment). If this is not possible, a string of the form <...some useful
description...> should be returned."
So I'd think the representation for dictionary views should look something like
this instead:
<dict_keys ['a', 'b']>
to indicate that it cannot be reproduced by a simple expression but still shows
it's contents.
----------
messages: 283808
nosy: Tadhg McDonald-Jensen
priority: normal
severity: normal
status: open
title: dict view string representations are misleading
type: behavior
versions: Python 2.7, Python 3.6, Python 3.7
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Python tracker <[email protected]>
<http://bugs.python.org/issue29043>
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