indexOf

Common
JVM
JS
Native
1.0
fun CharSequence.indexOf(
    char: Char,
    startIndex: Int = 0,
    ignoreCase: Boolean = false
): Int

Returns the index within this string of the first occurrence of the specified character, starting from the specified startIndex.

Parameters

ignoreCase - true to ignore character case when matching a character. By default false.

Return An index of the first occurrence of char or -1 if none is found.

Common
JVM
JS
Native
1.0
fun CharSequence.indexOf(
    string: String,
    startIndex: Int = 0,
    ignoreCase: Boolean = false
): Int

Returns the index within this char sequence of the first occurrence of the specified string, starting from the specified startIndex.

import java.util.Locale
import kotlin.test.*

fun main(args: Array<String>) {
//sampleStart
fun matchDetails(inputString: String, whatToFind: String, startIndex: Int = 0): String {
    val matchIndex = inputString.indexOf(whatToFind, startIndex)
    return "Searching for '$whatToFind' in '$inputString' starting at position $startIndex: " +
            if (matchIndex >= 0) "Found at $matchIndex" else "Not found"
}

val inputString = "Never ever give up"
val toFind = "ever"

println(matchDetails(inputString, toFind)) // Searching for 'ever' in 'Never ever give up' starting at position 0: Found at 1
println(matchDetails(inputString, toFind, 2)) // Searching for 'ever' in 'Never ever give up' starting at position 2: Found at 6
println(matchDetails(inputString, toFind, 10)) // Searching for 'ever' in 'Never ever give up' starting at position 10: Not found
//sampleEnd
}

Parameters

ignoreCase - true to ignore character case when matching a string. By default false.

Return An index of the first occurrence of string or -1 if none is found.