example-code-2e/08-def-type-hints/comparable/top.py
2021-08-07 00:44:01 -03:00

34 lines
747 B
Python

"""
``top(it, n)`` returns the "greatest" ``n`` elements of the iterable ``t``.
Example:
# tag::TOP_DOCTEST[]
>>> top([4, 1, 5, 2, 6, 7, 3], 3)
[7, 6, 5]
>>> l = 'mango pear apple kiwi banana'.split()
>>> top(l, 3)
['pear', 'mango', 'kiwi']
>>>
>>> l2 = [(len(s), s) for s in l]
>>> l2
[(5, 'mango'), (4, 'pear'), (5, 'apple'), (4, 'kiwi'), (6, 'banana')]
>>> top(l2, 3)
[(6, 'banana'), (5, 'mango'), (5, 'apple')]
# end::TOP_DOCTEST[]
"""
# tag::TOP[]
from collections.abc import Iterable
from typing import TypeVar
from comparable import SupportsLessThan
LT = TypeVar('LT', bound=SupportsLessThan)
def top(series: Iterable[LT], length: int) -> list[LT]:
ordered = sorted(series, reverse=True)
return ordered[:length]
# end::TOP[]