You cannot select more than 25 topics Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.

24 lines
675 B
Python

2 years ago
from setuptools.extern.more_itertools import consume # noqa: F401
# copied from jaraco.itertools 6.1
def ensure_unique(iterable, key=lambda x: x):
"""
Wrap an iterable to raise a ValueError if non-unique values are encountered.
>>> list(ensure_unique('abc'))
['a', 'b', 'c']
>>> consume(ensure_unique('abca'))
Traceback (most recent call last):
...
ValueError: Duplicate element 'a' encountered.
"""
seen = set()
seen_add = seen.add
for element in iterable:
k = key(element)
if k in seen:
raise ValueError(f"Duplicate element {element!r} encountered.")
seen_add(k)
yield element