Merge pull request #126 from Natgho/123-unique-function-fixing

123 unique function fixing

snippets/filter_unique.md

@@ -0,0 +1,17 @@
+---
+title: filter_unique
+tags: list,beginner
+---
+
+Filters out the unique values in a list.
+
+Use list comprehension and `list.count()` to create a list containing only the non-unique values.
+
+```py
+def filter_unique(lst):
+  return [x for x in set(item for item in lst if lst.count(item) > 1)]
+```
+
+```py
+filter_unique([1, 2, 2, 3, 4, 4, 5]) # [2, 4]
+```