String Functions

25 functions for trimming, casing, padding, and character-level string manipulation. The source column is always the implicit first input.

Function	Syntax	Parameters	Notes
`trim`	`trim(column)`	None.	Removes leading and trailing whitespace.
`ltrim`	`ltrim(column)`	None.	Removes leading whitespace only.
`rtrim`	`rtrim(column)`	None.	Removes trailing whitespace only.
`upper`	`upper(column)`	None.	Converts to uppercase.
`lower`	`lower(column)`	None.	Converts to lowercase.
`title_case`	`title_case(column)`	None.	Capitalizes the first letter of each word (Spark `initcap`).
`length`	`length(column)`	None.	Returns character length.
`concat`	`concat(column, values[])`	`values` — array of operands, each `{mode: "column"\|"literal"\|"expression", value}`.	Concatenates the source column with each operand in order. Legacy single-value/suffix form also supported.
`substring`	`substring(column, startPos, length)`	`startPos` default `1`. `length` default `1`.	1-indexed, matches Spark `substring()` semantics.
`pad_left`	`pad_left(column, length, padChar)`	`length` default `10`. `padChar` default `"0"`.	`F.lpad()`.
`pad_right`	`pad_right(column, length, padChar)`	`length` default `10`. `padChar` default `" "`.	`F.rpad()`.
`replace`	`replace(column, search, replace)`	`search`, `replace` — literal substrings.	Plain substring replace, not regex (see Regex category for pattern-based replace).
`reverse`	`reverse(column)`	None.	Reverses character order.
`concat_ws`	`concat_ws(column, separator, values[])`	`separator` default `","`. `values` — array of operands.	Concatenate-with-separator; nulls are skipped.
`left`	`left(column, length)`	`length` default `1`.	Leftmost N characters.
`right`	`right(column, length)`	`length` default `1`.	Rightmost N characters.
`position`	`position(column, search)`	`search` — substring to locate.	Returns 1-indexed position, 0 if not found.
`char_length`	`char_length(column)`	None.	Character count (alias of `length` for character semantics).
`octet_length`	`octet_length(column)`	None.	Byte length.
`bit_length`	`bit_length(column)`	None.	Bit length (`octet_length * 8`).
`translate`	`translate(column, fromChars, toChars)`	`fromChars`, `toChars` — matched character sets.	Character-by-character substitution, `F.translate()`.
`repeat`	`repeat(column, count)`	`count` default `2`.
`ascii_code`	`ascii_code(column)`	None.	ASCII code of the first character.
`char_from_code`	`char_from_code(column)`	None.	`CHR(CAST(column AS INT))` — inverse of `ascii_code`.
`soundex_difference`	`soundex_difference(column, otherColumn)`	`otherColumn` — column to compare against.	Compares Soundex codes of the two columns; returns a boolean/difference indicator.