[FEATURE] Improve filter_unique and filter_non_unique running time
mx-psi opened this issue · 1 comments
mx-psi commented
The filter_non_unique and filter_unique snippets currently have a quadratic running time; in both cases they count each item in the original list. This can be improved to linear time by using a counter from the collections module (at the expense of linear space).
Improvement of filter_unique
from collections import Counter
def filter_unique(lst):
counter = Counter(lst)
return [item for item, count in counter.items() if count > 1]Improvement of filter_non_unique
from collections import Counter
def filter_non_unique(lst):
counter = Counter(lst)
return [item for item, count in counter.items() if count == 1]Chalarangelo commented
If you can PR these changes along with their explanations, I'd be glad to merge them. Thanks for the feedback!