List Intersection (A ∩ B)
Find items that appear in both lists. Duplicates within a list collapse to a single result.
0 results
About List Intersection (A ∩ B)
List intersection produces only the items that appear in both input lists. It's the way to find what two lists have in common — overlapping emails, shared tags, common IDs.
When to use it
- Finding email addresses that appear on two mailing lists
- Identifying tags shared between two posts
- Computing overlap between two sets of IDs
- Auditing duplicates across two data sources
How it works
Both lists are split on LF/CRLF, blank lines are dropped. A Set is built from list B's items. The result is each item from list A that is also in B, in A's original order, deduplicated.
Examples
A: apple, banana, cherry B: banana, cherry, date
banana cherry
Frequently asked questions
- Is the order based on list A or list B?
- List A. The result preserves A's order for items also found in B.
- Are duplicates within a list considered?
- Each item is counted once per list. The intersection is a set, not a multiset.