Add padding to a string in Kotlin

This article explores different ways to add padding to a string in Kotlin.

1. Using `format()` function

A common solution to left/right pad a string with spaces is using the format() function. For example,

fun padLeft(s: String?, n: Int): String {

return "%${n}s".format(s)

}

fun padRight(s: String?, n: Int): String {

return "%-${n}s".format(s)

}

fun main() {

val s = "ABC"

val n = 5

println(padLeft(s, n)) // " ABC"

println(padRight(s, n)) // "ABC "

}

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We can left-pad a numeric string with zeros by converting it to an integer and using the '0' flag, as shown below:

fun padLeft(s: String, n: Int): String {

return "%0${n}d".format(s.toInt())

}

fun main() {

val s = "1011101"

val n = 16

println(padLeft(s, n)) // 0000000001011101

}

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2. Using `padStart()` and `padEnd()` function

Alternatively, we can use the padStart() library function to pad a string to the specified length, at the beginning, with the specified character or space. Similarly, the padEnd() library function can be used to pad a string to the specified length, at the end, with the specified character or space.

fun padLeft(s: String, n: Int): String {

return s.padStart(n, ' ')

}

fun padRight(s: String, n: Int): String {

return s.padEnd(n, ' ')

}

fun main() {

val s = "ABC"

val n = 5

println(padLeft(s, n)) // "00ABC"

println(padRight(s, n)) // "ABC00"

}

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That’s all about adding padding to a string in Kotlin.

Add padding to a string in Kotlin

1. Using format() function

2. Using padStart() and padEnd() function

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1. Using `format()` function

2. Using `padStart()` and `padEnd()` function