Python annotation's type for nested list with mix of numbers and lists
Question:
It is known that an annotation’s type for [[1, 2, 3], [4, 5, 6], [7, 8, 9]] is List[List[int]]. But what is the annotation’s type for nested list with mix of numbers and lists [[1, 1], 2, [1 , 1]]?
Answers:
Typing has evolved a lot in recent python version, after all it was introduced recently, therefore depending on which version you’re using, the typing signature will be different.
Type of [[1, 2, 3], [4, 5, 6], [7, 8, 9]]:
python version
type
>= 3.6
typing.List[typing.List[int]]
>= 3.9
list[list[int]]
Type of [[1, 1], 2, [1 , 1]]:
python version
type
>= 3.6
typing.List[typing.Union[typing.List[int], int]]
>= 3.9
list[typing.Union[list[int], int]]
>= 3.10
list[list[int] | int]
It is known that an annotation’s type for [[1, 2, 3], [4, 5, 6], [7, 8, 9]] is List[List[int]]. But what is the annotation’s type for nested list with mix of numbers and lists [[1, 1], 2, [1 , 1]]?
Typing has evolved a lot in recent python version, after all it was introduced recently, therefore depending on which version you’re using, the typing signature will be different.
Type of [[1, 2, 3], [4, 5, 6], [7, 8, 9]]:
| python version | type |
|---|---|
| >= 3.6 | typing.List[typing.List[int]] |
| >= 3.9 | list[list[int]] |
Type of [[1, 1], 2, [1 , 1]]:
| python version | type |
|---|---|
| >= 3.6 | typing.List[typing.Union[typing.List[int], int]] |
| >= 3.9 | list[typing.Union[list[int], int]] |
| >= 3.10 | list[list[int] | int] |