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is_sequence_of

FunctionSource

flag: TypeGuard[[T]] = is_sequence_of(
    data: Any,
    validator: type[T] | (Any) => TypeGuard[T],
)

Check whether data is Sequence[T], where T is specified by validator.

Aliases​

This function can be acquired by

import dash_picture_annotation as dpa


dpa.is_sequence_of
dpa.typehints.is_sequence_of

Arguments​

Requires​

ArgumentTypeRequired
Description
dataAnyThe value to be verified.
validatortype[T] | (Any) => TypeGuard[T]The validator. It can be a type or a function validating whether a value is of a specific type.

Returns​

ArgumentType
Description
flagboolIf this value is True, data is a sequence of the instance of T determined by validator, vice versa.

Examples​

Check whether an object is a list of int​

check_is_sequence_of_int.py
import dash_picture_annotation as dpa


print(dpa.is_sequence_of([], int))
print(dpa.is_sequence_of((1,), int))
print(dpa.is_sequence_of([1, 2, 3], int))
print(dpa.is_sequence_of([1, 2, 3, 4.0], int))

Check whether an object is a list of a customized type​

check_is_sequence_of_hascopy.py
from typing import Any
from typing_extensions import TypeGuard, Protocol, Self
import dash_picture_annotation as dpa


class HasCopy(Protocol):
    def copy(self: Self) -> Self: ...


def is_has_copy(val: Any) -> TypeGuard[HasCopy]:
    return callable(getattr(val, "copy", None))


print(dpa.is_sequence_of([[], [], []], is_has_copy))
print(dpa.is_sequence_of([tuple(), [], []], is_has_copy))
print(dpa.is_sequence_of([dict(),], is_has_copy))
print(dpa.is_sequence_of(["", "", ""], is_has_copy))
print(dpa.is_sequence_of([[], dict()], is_has_copy))
print(dpa.is_sequence_of([[], dict(), tuple()], is_has_copy))

Check whether an object is a list of annotation items​

check_is_sequence_of_annoitem.py
import dash_picture_annotation as dpa

example_empty = []
example_one_item = dpa.AnnoItem(
    id="test", mark=dpa.AnnoMark(x=0, y=0, width=0, height=0, type="RECT")
)
example_item_single_tuple = (example_one_item,)
example_items = [example_one_item, example_one_item, example_one_item]
example_items_bad = [example_one_item, dict(id="test", mark={"x": 1})]

print(dpa.is_sequence_of(example_empty, dpa.is_anno_item))
print(dpa.is_sequence_of(example_one_item, dpa.is_anno_item))
print(dpa.is_sequence_of(example_item_single_tuple, dpa.is_anno_item))
print(dpa.is_sequence_of(example_items, dpa.is_anno_item))
print(dpa.is_sequence_of(example_items_bad, dpa.is_anno_item))