Kotlin Extensions

Extensions.md

Kotlin Extensions

This gist will host some nice extensions for anything Kotlin.

Double.kt

/**
 * Rounds a [Double] to [numberOfPlaces].
 */
fun Double.roundTo(numberOfPlaces: Int): Double {
    return round(this*10.0.pow(numberOfPlaces))/10.0.pow(numberOfPlaces)
}

/**
 * Returns the decimal part of a [Double].
 */
val Double.decimal get() = this % toInt()

Int.kt

/**
 * Equivalent of [String.isNullOrEmpty] for [Int].
 *
 * @see [String.isNullOrEmpty]
 * @see [String.isNullOrBlank]
 */
fun Int?.isNullOrZero(): Boolean = this == 0 || this == null

FlaotToFloat.kt

/**
 * Integrate a function (lambda) from [from] to [to].
 */
fun ((Float) -> Float).integrate(
    from: Float, 
    to: Float, 
    dx: Float
): Float {
    var at = from
    var integral = 0f
    while(at < to) {
	integral += this(at) * dx
        at += dx
    }
    return integral
}