zulip/zerver/lib/query.py

19 lines
501 B
Python

from __future__ import absolute_import
from django.db.models.query import QuerySet
from typing import TypeVar, List
T = TypeVar('T')
def last_n(n, query_set):
# type: (int, QuerySet[T]) -> List[T]
"""Get the last n results from a Django QuerySet, in a semi-efficient way.
Returns a list."""
# We don't use reversed() because we would get a generator,
# which causes bool(last_n(...)) to be True always.
xs = list(query_set.reverse()[:n])
xs.reverse()
return xs