diff options
Diffstat (limited to 'third_party/python/setuptools/pkg_resources/_vendor/importlib_resources/_itertools.py')
-rw-r--r-- | third_party/python/setuptools/pkg_resources/_vendor/importlib_resources/_itertools.py | 35 |
1 files changed, 35 insertions, 0 deletions
diff --git a/third_party/python/setuptools/pkg_resources/_vendor/importlib_resources/_itertools.py b/third_party/python/setuptools/pkg_resources/_vendor/importlib_resources/_itertools.py new file mode 100644 index 0000000000..cce05582ff --- /dev/null +++ b/third_party/python/setuptools/pkg_resources/_vendor/importlib_resources/_itertools.py @@ -0,0 +1,35 @@ +from itertools import filterfalse + +from typing import ( + Callable, + Iterable, + Iterator, + Optional, + Set, + TypeVar, + Union, +) + +# Type and type variable definitions +_T = TypeVar('_T') +_U = TypeVar('_U') + + +def unique_everseen( + iterable: Iterable[_T], key: Optional[Callable[[_T], _U]] = None +) -> Iterator[_T]: + "List unique elements, preserving order. Remember all elements ever seen." + # unique_everseen('AAAABBBCCDAABBB') --> A B C D + # unique_everseen('ABBCcAD', str.lower) --> A B C D + seen: Set[Union[_T, _U]] = set() + seen_add = seen.add + if key is None: + for element in filterfalse(seen.__contains__, iterable): + seen_add(element) + yield element + else: + for element in iterable: + k = key(element) + if k not in seen: + seen_add(k) + yield element |