I think one function returning multiple types must be confusing.
You should use `functools.partial` or create new function with def or lambda.
>> from functools import partial
>>
>> pass_filter = partial(filter, lambda x: x > 60)
>> foo = [42, 56, 67, 87]
>> for i in pass_filter(foo):
>> print(i)
>>
>> # 67
>> # 87
> 2021/02/11 23:04、Henry Harutyunyan <henryharutyun...@gmail.com>のメール:
>
> One of my students gave me an interesting question about why `filter` and
> `map` do not return a reusable function in case the iterable is not passed.
>
> With the current design
> ```
> In [1]: a = filter(lambda x: x > 60)
> ---------------------------------------------------------------------------
> TypeError Traceback (most recent call last)
> <ipython-input-1-ad0178d4fce0> in <module>
> ----> 1 a = filter(lambda x: x > 60)
>
> TypeError: filter expected 2 arguments, got 1
> ```
>
> this is fine as long as you need to use that filter for once. But if you want
> to reuse it you either need to create the iterator every time specifying the
> filter function, or save the function in a var and create the filter with
> that.
>
> I'm wondering why can't we create custom filters and mappers that are
> reusable. The result will look something like this:
>
> ```
>>>> pass_filter = filter(lambda x: x > 60)
>>>> foo = [42, 56, 67, 87]
>>>> for i in pass_filter(foo):
>>>> print(i)
> 67
> 86
>>>> bar = {45, 94, 65, 3}
>>>> for i in pass_filter(bar):
>>>> print(i)
> 65
> 94
> ```
> Are there any drawbacks or limitations to this? Is is worth working on?
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