Text · listsList processing

anna@example.com petr@example.com

Paste the list, set the input separator to «line break» and the output separator to «comma». The column becomes a single line with values joined by a comma and a space, which reads well and pastes straight back into text. The reverse task works the same way with the separators swapped: comma in, line break out. Everything recalculates as you type — there is no «convert» button to press.

Turn on «remove duplicates»: identical lines collapse into one and the order of first appearance is kept. The «ignore case» switch treats «Apple» and «apple» as the same value, and «keep first or last» decides which of the repeated entries survives — the last one stays where it is in the tail rather than jumping to the top. The statistics line under the result says how many duplicates were removed.

Deduplication leaves every value once and says nothing about how many there were. A frequency list answers a different question — how often each value occurs: repeated entries get a «apple ×3» mark and the list is ordered by count, from the most frequent down. Values with the same count keep their original order, because that is the only order a person can predict from their own list.

Alphabetical sorting compares strings character by character, so «file10» lands before «file2»: the character «1» is smaller than «2». Natural sorting reads the digits as a whole number and produces file1, file2, file10 — the order people actually expect from file names, versions and numbered items. Besides these two there is sorting by length, a random shuffle and the reverse of any of them.

Pick a wrapping preset: quotes, SQL, HTML, JSON, Markdown or CSV. Two of them wrap the whole list rather than each line — SQL builds an «IN (…)» clause and JSON produces a valid array — while the rest add the wrapper to every line. Values are escaped along the way: an apostrophe inside a value will not break the SQL statement and a quote will not break the JSON. For anything else, set your own prefix and suffix.

Open «Compare lists», paste both lists and choose an operation: intersection shows what they share, «only in A» and «only in B» show the difference, union merges them without duplicates. Statistics next to the result say how many lines each list had and how many are common. Nothing is sent anywhere: the whole thing runs in your browser, so lists of emails, phone numbers or orders are safe to paste.