ToDegrees¶

Overview¶

The ToDegrees expression converts an angle value from radians to degrees. This is a unary mathematical expression that applies the standard radian-to-degree conversion formula by multiplying the input by 180/π.

Syntax¶

DEGREES(angle_in_radians)

degrees(col("angle_column"))

Arguments¶

Argument	Type	Description
child	Expression	The angle value in radians to convert to degrees

Return Type¶

Double - returns a floating-point number representing the angle in degrees.

Supported Data Types¶

Numeric types (Int, Long, Float, Double, Decimal)
The expression internally uses math.toDegrees which operates on Double values
Non-numeric inputs will cause a cast or runtime error

Algorithm¶

Takes the input angle value in radians as a Double
Applies the Java math.toDegrees function internally
Uses the conversion formula: degrees = radians × (180/π)
Returns the result as a Double value
Inherits evaluation logic from UnaryMathExpression base class

Partitioning Behavior¶

How this expression affects partitioning:

Preserves partitioning as it's a unary expression that doesn't require data movement
Does not require shuffle operations
Can be applied per-partition independently

Edge Cases¶

Null input returns null (standard Spark null propagation)
Handles positive and negative radian values correctly
Very large input values may result in overflow to infinity
Very small input values near zero are handled precisely
NaN input produces NaN output

Code Generation¶

This expression supports Tungsten code generation through the UnaryMathExpression base class, which generates efficient native code for the mathematical operation rather than falling back to interpreted mode.

Examples¶

-- Convert π radians to degrees
SELECT DEGREES(3.141592653589793);
-- Result: 180.0

-- Convert π/2 radians to degrees  
SELECT DEGREES(1.5707963267948966);
-- Result: 90.0

-- Handle negative values
SELECT DEGREES(-3.141592653589793);
-- Result: -180.0

// DataFrame API usage
import org.apache.spark.sql.functions.degrees

df.select(degrees(col("radian_column")))

// Convert literal value
df.select(degrees(lit(math.Pi)))