The operations
| Operation | What it does |
|---|---|
| Remove duplicates | keeps the first occurrence of each line |
| Sort A→Z, Z→A | natural sort, so item2 comes before item10 |
| Sort by length | shortest first, alphabetical within the same length |
| Shuffle | random order, for sampling or for drawing names |
| Reverse order | last line first |
| Trim spaces | removes leading and trailing whitespace from every line |
| Remove empty lines | deletes every blank line |
| Collapse blank runs | several blank lines become one |
| Number lines | adds 1., 2., padded so the numbers align |
| Add prefix/suffix | wraps every line in text you choose: quotes around each name, a dash before each entry |
| Join into one line | with a separator you choose |
The order that usually works
Most lists arrive messy in the same way: copied out of a spreadsheet or a PDF, with stray spaces and repeated entries.
Trim first, because a trailing space makes two identical lines look different to the deduplicator. Then remove duplicates. Then sort. Doing it in the other order leaves duplicates behind, and that is the single most common reason people think a deduplicator is broken.
Ignore case, precisely
The checkbox changes how lines are compared, never what is written out. With it on, Berlin and berlin count as the same entry and the first one wins, keeping its original spelling. Sorting likewise groups them rather than putting all capitals first.
Leaving it off is the right choice whenever capitals matter: file names or product codes where ABC and abc are genuinely different things.
Building a list for code
Add prefix and suffix turns a column of values into something you can paste. Prefix ' and suffix ', gives you a quoted, comma-separated list; join into one line with , gives you one line of values. Both keep the original order unless you sort first.
Questions
Does sorting handle numbers correctly?
Yes. Sorting is natural, so item2 comes before item10 rather than after it, which is what people expect from a list of files or versions.
What does ignore case do?
It affects comparison, not output. With it on, Apple and apple count as duplicates and sort together, but the original spelling is kept.
What is the difference between removing empty lines and collapsing blank runs?
Removing empty lines deletes every one. Collapsing keeps a single blank line where there were several, which is what you usually want for prose.
Can I chain operations?
Yes. Press Result → input and apply the next one. Trim, then remove duplicates, then sort is the common sequence.
Is my list uploaded?
No. It is processed in your browser, and a draft is kept in this browser's local storage so a reload does not lose it.