Coverage for /pythoncovmergedfiles/medio/medio/usr/local/lib/python3.8/site-packages/pkg_resources/_vendor/importlib_resources/_itertools.py: 0%

1from itertools import filterfalse 

2 

3from typing import ( 

4 Callable, 

5 Iterable, 

6 Iterator, 

7 Optional, 

8 Set, 

9 TypeVar, 

10 Union, 

11) 

12 

13# Type and type variable definitions 

14_T = TypeVar('_T') 

15_U = TypeVar('_U') 

16 

17 

18def unique_everseen( 

19 iterable: Iterable[_T], key: Optional[Callable[[_T], _U]] = None 

20) -> Iterator[_T]: 

21 "List unique elements, preserving order. Remember all elements ever seen." 

22 # unique_everseen('AAAABBBCCDAABBB') --> A B C D 

23 # unique_everseen('ABBCcAD', str.lower) --> A B C D 

24 seen: Set[Union[_T, _U]] = set() 

25 seen_add = seen.add 

26 if key is None: 

27 for element in filterfalse(seen.__contains__, iterable): 

28 seen_add(element) 

29 yield element 

30 else: 

31 for element in iterable: 

32 k = key(element) 

33 if k not in seen: 

34 seen_add(k) 

35 yield element