Read File Content as List of Lines in Kotlin

To read file content as List of lines, use File.readLines() method.

In this tutorial, we will learn how to read file content as a list of lines in Kotlin.

The function used to read the lines from a text file is

MethodDescription
File.readLines()Reads file content as a list of lines

Example 1 – Read Lines in Text file as List

In this example, we will read a text file, “file.txt”, present at the root of the project. We will use File.readLines() method.

file.txt

Hello World.
Welcome to Kotlin Tutorial by www.tutorialkart.com.
Learning Kotlin is easy.

example.kt

import java.io.File

/**
 * Kotlin Example to read contents of file line by line
 */
fun main(args: Array) {
    val fileName :String = "file.txt"
    var i :Int = 1
    // using extension function readLines
    File(fileName).readLines().forEach {
        print((i++))
        println(": "+it)
    }
}

Output

1: Hello World.
2: Welcome to Kotlin Tutorial by www.tutorialkart.com.
3: Learning Kotlin is easy.
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Conclusion

In this Kotlin Tutorial – Kotlin Read File to Lines, we have learnt to read content of file line by line. In our next tutorial, we shall learn to write data to file.