subscription

utilitools.subscription(type=None, /)

Transforms a function into a subscription object.

Subscription applies to objects that behave as sequences.

Attention

• The object must accept precisely one positional argument if it is a function.

• The object must not accept arguments at all if it is a generator.

Parameters

type (collections.Callable) –

The returned data type when the key is slice.

By default, returned utilitools.islice.

Returns

A subscription object that already implements the __getitem__ magic method.

Return type

utilitools.utilities.Subscription

Raises

TypeError –

• If type is not a callable that accepts an iterator.

• If the function does not accept one positional argument.

• If the generator accepts at least one argument.

• If the key is not int or slice.

Examples

from utilitools import subscription

@subscription(tuple)
def digital_sum(n):
    return sum(map(int, str(n)))

@subscription(list)
def fibonacci():
    a, b = 0, 1
    yield a
    while True:
        a, b = b, a + b
        yield a

Subscription from a function when the key is int:

>>> digital_sum[123]
6

Subscription from a generator when the key is int:

>>> fibonacci[123]
22698374052006863956975682

Subscription from a function when the key is slice while the type is a tuple:

>>> digital_sum[10:20:3]
(1, 4, 7, 10)

Subscription from a generator when the key is slice while the type is a list:

>>> fibonacci[10:20:3]
[55, 233, 987, 4181]