StringTrimRight¶

Overview¶

StringTrimRight is a Spark Catalyst expression that removes trailing whitespace or specified characters from the right side of a string. It supports both single-argument mode (trimming whitespace) and two-argument mode (trimming specific characters) with collation-aware string operations.

Syntax¶

RTRIM(string_expr)
RTRIM(string_expr, trim_chars)

// DataFrame API
rtrim(col("column_name"))
rtrim(col("column_name"), lit("chars_to_trim"))

Arguments¶

Argument	Type	Description
srcStr	Expression	The source string expression to trim characters from
trimStr	Option[Expression]	Optional expression specifying characters to trim. If None, trims whitespace

Return Type¶

UTF8String - Returns a string with trailing characters removed from the input string.

Supported Data Types¶

StringTypeNonCSAICollation with trim collation support - accepts string types that support collation-aware trimming operations but excludes case-sensitive accent-insensitive collations.

Algorithm¶

Evaluates the source string expression to get UTF8String input
If trimStr is None, delegates to CollationSupport.StringTrimRight.exec(srcString) for whitespace trimming
If trimStr is provided, evaluates the trim string and calls CollationSupport.StringTrimRight.exec(srcString, trimString, collationId)
Uses collation-aware string operations to handle different character encodings and locale-specific rules
Returns the trimmed UTF8String result

Partitioning Behavior¶

This expression preserves partitioning:

Does not require shuffle operations as it operates on individual rows
Maintains existing data distribution since it's a row-level transformation
Can be pushed down to individual partitions for parallel execution

Edge Cases¶

Null handling: If srcStr evaluates to null, returns null
Empty string: Returns empty string unchanged
Null trimStr: Treated as None, falls back to whitespace trimming
Empty trimStr: No characters are trimmed, returns original string
Collation-specific behavior applies for character matching and comparison

Code Generation¶

This expression supports Catalyst code generation through the String2TrimExpression base class, enabling efficient Tungsten code generation for improved runtime performance.

Examples¶

-- Trim trailing whitespace
SELECT RTRIM('  hello world  ') AS result;
-- Result: '  hello world'

-- Trim specific trailing characters
SELECT RTRIM('xxxhelloxxx', 'x') AS result;
-- Result: 'xxxhello'

// DataFrame API - trim whitespace
df.select(rtrim(col("text_column")))

// DataFrame API - trim specific characters
df.select(rtrim(col("text_column"), lit("xyz")))