Comma to Column Converter

Comma-delimited strings are the default interchange format for spreadsheets, log files, and API query parameters. Manually splitting them into one-item-per-line columns introduces transcription errors and wastes time that compounds across hundreds of records. This tool parses an input string by a configurable delimiter (comma , by default), trims surrounding whitespace from each token, and outputs a vertical column. It also handles edge cases: consecutive delimiters producing empty tokens, trailing delimiters, and mixed whitespace. The reverse operation - column back to comma string - is equally supported. Optional deduplication uses a hash-set pass in O(n) time, and lexicographic sorting follows the Unicode default collation. Note: the tool treats the delimiter literally; regular-expression patterns are not supported to avoid ReDoS vectors in user-supplied input.

The conversion is a deterministic string-split operation. Given an input string S and a delimiter character d, the output column C is defined as:

Where split(S, d) produces an array of n tokens, trim removes leading and trailing whitespace from each token, and join concatenates them with a newline character. When deduplication is enabled, a Set filter is applied before joining, reducing the array to unique elements in O(n) average time. The reverse operation inverts the axes: split by newline, join by d.

Where S = input string, d = delimiter character, C = output column, n = number of resulting tokens.