How to use this tool
- Paste one item per line into List A and List B. Commas are part of an item, not separators.
- Select whether to show shared items, items unique to either side, the symmetric difference, or all unique items.
- Set trimming and case matching, then compare the output count with the unique counts for each input.
Understanding the output
Each distinct matching key counts once. Repeated entries do not increase the totals. Output preserves the first spelling encountered in its source list, after optional trimming. Shared entries use List A’s spelling; a combined result lists A items before new B items.
For cleaning repetition within just one list, use Remove Duplicate Lines and choose its whitespace and case options.
Checking overlapping fruit lists
List A contains apple, pear, apple on separate lines. List B contains pear and plum. In both lists returns pear; Only in A returns apple; Only in B returns plum. All unique items returns apple, pear, plum in that order, with duplicate apple counted once.
Membership and quantity answer different questions
A stock list with three occurrences of the same product and another with one occurrence have the same membership for that product. This comparison treats lists as sets, so it cannot reconcile quantities, transaction totals, or duplicate record counts. Include a stable identifier as each line when names alone could refer to different records.
Choose normalization to match the data
Trimming helps when pasted spreadsheet cells have accidental spaces at their edges. Case-insensitive matching can help with labels, but it may incorrectly merge case-sensitive identifiers. Neither option standardizes punctuation, internal spaces, accents, or Unicode normalization. Check those details before treating the output as a complete reconciliation.
Method and supported input
Each input is limited to 100,000 UTF-16 code units and split on CRLF, CR, or LF. Empty items are discarded after optional trimming; a spaces-only line remains an item if trimming is off.
The first occurrence of each comparison key is retained. Intersection keeps A keys also in B; differences keep absent keys; the union appends B-only items to A. Case-insensitive keys use JavaScript lowercase conversion.
- One logical item occupies one line.
- Duplicate frequency and original cross-list ordering are not part of equality.
Limitations
- The tool does not parse CSV records, quoted multiline cells, or tables.
- Matching is exact after the selected transformations; there is no fuzzy matching.
- A lowercase comparison is not a full linguistic equivalence test.
Common questions
Are duplicate entries removed?
Yes. Every operation returns unique matching keys, even when an entry occurs several times in either input.
What is the symmetric difference?
It contains items found in exactly one list: A-only entries followed by B-only entries. Shared entries are excluded.
Why do accented words sometimes fail to match?
Different Unicode sequences can look alike. This tool does not normalize those sequences or remove accents, so visually similar entries may remain distinct.