StringSpace¶

Overview¶

The StringSpace expression creates a string consisting of a specified number of space characters. It takes an integer argument representing the desired length and returns a UTF-8 string filled with that many spaces.

Syntax¶

SPACE(length)

// DataFrame API usage
import org.apache.spark.sql.functions._
space(col("length_column"))

Arguments¶

Argument	Type	Description
length	Integer	The number of space characters to generate

Return Type¶

UTF8String - A string containing the specified number of space characters.

Supported Data Types¶

Input: IntegerType only
Implicit casting is supported for compatible numeric types that can be cast to integer

Algorithm¶

Validates that the input is an integer type through implicit cast input types
Evaluates the length parameter as an integer value
If the length is negative, it defaults to 0 (no spaces)
Uses UTF8String.blankString() to efficiently generate a string of spaces
Returns the resulting UTF-8 string with the specified number of spaces

Partitioning Behavior¶

This expression preserves partitioning behavior:

Does not require shuffle operations
Can be evaluated independently on each partition
Does not affect data distribution or partitioning scheme

Edge Cases¶

Null handling: Expression is null-intolerant, meaning null inputs result in null output
Negative values: Negative length values are treated as 0, resulting in an empty string
Zero length: Returns an empty string when length is 0
Large values: Limited by available memory and UTF8String implementation constraints

Code Generation¶

This expression supports Tungsten code generation through the doGenCode method:

Implements nullSafeCodeGen for efficient compiled code execution
Generates optimized bytecode that avoids object creation overhead
Falls back to interpreted mode only when code generation is disabled

Examples¶

-- Basic usage
SELECT SPACE(5);
-- Result: '     ' (5 spaces)

-- With negative number
SELECT SPACE(-3);
-- Result: '' (empty string)

-- Combined with other functions
SELECT CONCAT(SPACE(2), '1');
-- Result: '  1'

-- Using with column values
SELECT name, SPACE(padding_length) AS spaces FROM table;

// DataFrame API examples
import org.apache.spark.sql.functions._

// Basic usage
df.select(space(lit(5)))

// With column reference
df.select(space(col("length_column")))

// Combined with other functions
df.select(concat(space(lit(3)), col("text")))