CODEWITHSUNDEEP
pythonpython-typing
Vlad Aleshin
Vlad Aleshin

Reputation: 411

Type hints for sequences of str

I have a function:

def f(a: Sequence[str], b: Sequence[str]) -> List[str]:   
    return list(set(a) - set(b))
a = ['a', 'b', 'c']
b = ['b', 'c']
f(a, b)

But this function can be applicable not only for str type but for other types that can be comparable (int, float, etc.). In this case how to set up type hints for a and b parameters?

Upvotes: 1

Views: 1515

Answers (1)

borisdonchev
borisdonchev

Reputation: 1224

You should use the Any Type if you are not sure

from typing import Any
def f(a: Sequence[Any], b: Sequence[Any]) -> List[Any]:   
    return list(set(a) - set(b))
a = ['a', 'b', 'c']
b = ['b', 'c']
f(a, b)

If you want to make it applicable only to those three types (int, float, str), you should use Union:

from typing import Union
def f(a: Sequence[Union[str, int, float]], b: Sequence[Union[str, int, float]]) -> List[Union[str, int, float]]:   
    return list(set(a) - set(b))
a = ['a', 'b', 'c']
b = ['b', 'c']
f(a, b)

As of python 3.10 the union type can be omitted and you can write it directly like so:

a: Sequence[str|int|float]

Upvotes: 2

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