List to comma separated

Turns a column of lines into a single comma-separated line, trimming whitespace and dropping empties. The reverse direction is one button away.

The everyday version of this is pasting a spreadsheet column into a SQL IN clause, a config value or a form field that wants comma separation. Trimming matters more than it looks: a value with a trailing space will not match anything downstream, and the space is invisible in the source. If your items themselves contain commas, this is the wrong tool — the result is ambiguous and a proper CSV writer that quotes the values is what you need. Changing the separator to a semicolon or a pipe is the quick workaround when the data contains commas but you control both ends.