Kotlin String repeat

The repeat function in Kotlin is used to create a new string by repeating the original string a specified number of times. This function belongs to the String class in the Kotlin standard library and provides a straightforward way to repeat a string.

Table of Contents

1. Introduction
2. repeat Function Syntax
3. Understanding repeat
4. Examples
   • Basic Usage
   • Using repeat with Different Counts
5. Real-World Use Case
6. Conclusion

Introduction

The repeat function generates a new string by repeating the original string a specified number of times. This is useful for tasks such as creating patterns, generating repeated content, and formatting output.

repeat Function Syntax

The syntax for the repeat function is as follows:

fun String.repeat(n: Int): String

Parameters:

• n: The number of times to repeat the original string. This must be a non-negative integer.

Returns:

• A new string that consists of the original string repeated n times.

Throws:

• IllegalArgumentException if n is negative.

Understanding repeat

The repeat function concatenates the original string with itself n times to create a new string. If n is 0, the function returns an empty string.

Examples

Basic Usage

To demonstrate the basic usage of repeat, we will create a string and repeat it a specified number of times.

Example

fun main() {
    val text = "Hello"
    val repeatedText = text.repeat(3)
    println("Original text: $text")
    println("Repeated text: $repeatedText")
}

Output:

Original text: Hello
Repeated text: HelloHelloHello

Using repeat with Different Counts

This example shows how to use repeat with different repeat counts.

Example

fun main() {
    val text = "Kotlin"

    val repeatedOnce = text.repeat(1)
    val repeatedTwice = text.repeat(2)
    val repeatedZeroTimes = text.repeat(0)

    println("Original text: $text")
    println("Repeated once: $repeatedOnce")
    println("Repeated twice: $repeatedTwice")
    println("Repeated zero times: '$repeatedZeroTimes'")
}

Output:

Original text: Kotlin
Repeated once: Kotlin
Repeated twice: KotlinKotlin
Repeated zero times: ''

Real-World Use Case

Creating a Divider Line

In real-world applications, the repeat function can be used to create repeated patterns, such as a divider line made of hyphens.

Example

fun main() {
    val line = "-".repeat(30)
    println(line)
    println("Title")
    println(line)
}

Output:

------------------------------
Title
------------------------------

Conclusion

The repeat function in Kotlin's String class is a convenient method for creating a new string by repeating the original string a specified number of times. It provides a simple way to generate repeated content for various use cases, including formatting, pattern creation, and generating repeated content. 

By understanding and using this function, you can effectively manage string repetition in your Kotlin applications.