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indexOfFirst

Platform and version requirements: JVM (1.0), JS (1.0), Native (1.0)
inline fun CharSequence.indexOfFirst(
    predicate: (Char) -> Boolean
): Int

Returns index of the first character matching the given predicate, or -1 if the char sequence does not contain such character.

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Licensed under the Apache License, Version 2.0.
https://kotlinlang.org/api/latest/jvm/stdlib/kotlin.text/index-of-first.html