New submission from HuangFuSL <huangf...@outlook.com>:
When I am creating a counter object provided by `collections.Counter` using a
mapping object like a dictionary, it seems that Python will not check the
validity of the values in the mapping object.
I've checked the following Python script could be successfully executed using
Python 3.9.0 on Windows.
```python
>>> from collections import Counter
>>> a = Counter({'0': '0'})
>>> a.elements()
<itertools.chain object at 0x00000252DDB5A4F0>
```
`a.elements()` returns a iterator, iterating through it will normally get the
records counted by the `Counter`, but with a `str` object inside, iterating
through it will make a `TypeError` raised.
```python
>>> for i in a.elements():
... pass
...
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
TypeError: 'str' object cannot be interpreted as an integer
```
Meanwhile, if the counter contains values that cannot be compared such as
`False` and `''`, `most_common()` method will fail.
```python
>>> b = Counter({'0': False, '1': ''})
>>> b.most_common()
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "C:\Python39\lib\collections\__init__.py", line 610, in most_common
return sorted(self.items(), key=_itemgetter(1), reverse=True)
TypeError: '<' not supported between instances of 'bool' and 'str'
```
The `sys.version` variable of my Python interpreter is as follows:
```
>>> import sys
>>> sys.version
'3.9.0 (tags/v3.9.0:9cf6752, Oct 5 2020, 15:34:40) [MSC v.1927 64 bit (AMD64)]'
>>>
```
I'm not sure whether the result is intentionally designed, but I think such
execution results may lead to confusion.
----------
components: Extension Modules
messages: 385913
nosy: HuangFuSL
priority: normal
severity: normal
status: open
title: Non-integer values in collections.Counter
type: behavior
versions: Python 3.9
_______________________________________
Python tracker <rep...@bugs.python.org>
<https://bugs.python.org/issue43062>
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