Kotlin - Numbers

Types

• Byte
• Short
• Int
• Long
• Float
• Double

Convert string to number

package examples

fun main() {

    println("1.01".toIntOrNull()) // null (not 1)

    println("1".toInt())

    println("1.01".toDouble())

    println("1.01".toBigDecimal())

    println("1.01e".toBigDecimal()) // NumberFormatException

}

Convert int to double

package examples

fun main() {

    val i = 1

    val d = 0.5

    println(i - d) // 0.5

    println(i.javaClass)  // int

    println(i.toDouble()) // 1.0

}

Format number to string: %

package examples

fun main() {

    println("%.2f".format(1.123456)) // 1.12

}

Convert Double to Int

package examples

import kotlin.math.roundToInt

fun main() {

    val d15 = 1.5

    val d14 = 1.4

    println(d15.roundToInt()) // 2

    println(d14.roundToInt()) // 1

    println(d15.toInt()) // 1

    println(d14.toUInt()) // 1

    val md15 = -1.5

    val md14 = -1.4

    println(md15.roundToInt()) // -1

    println(md14.roundToInt()) // -1

    println(md15.toInt()) // -1

    println(md14.toUInt()) // 0

}