kotlin-stdlib/kotlin.text/toLongOrNull

toLongOrNull

fun String.toLongOrNull(): Long?(source)

Parses the string to a Long number or returns null if the string is not a valid representation of a Long.

The string must consist of an optional leading + or - sign and decimal digits (0-9), and fit the valid Short value range (within Long.MIN_VALUE..Long.MAX_VALUE), otherwise null is returned.

Since Kotlin

1.1

Samples

import kotlin.test.assertFailsWith

fun main() { 
   //sampleStart 
   println("0".toLongOrNull()) // 0
println("42".toLongOrNull()) // 42
println("042".toLongOrNull()) // 42
println("-42".toLongOrNull()) // -42
// Long.MAX_VALUE
println("9223372036854775807".toLongOrNull()) // 9223372036854775807
// Long overflow
println("9223372036854775808".toLongOrNull()) // null
// 'a' is not a digit
println("-1a".toLongOrNull()) // null
// underscore
println("1_00".toLongOrNull()) // null
// whitespaces
println(" 22 ".toLongOrNull()) // null 
   //sampleEnd
}
fun String.toLongOrNull(radix: Int): Long?(source)

Parses the string as a Long number and returns the result or null if the string is not a valid representation of a number.

Since Kotlin

1.1

Throws

when radix is not a valid radix for string to number conversion.