kotlin-stdlib/kotlin.collections/indexOf

indexOf

fun <T> Array<out T>.indexOf(element: T): Int(source)
fun ByteArray.indexOf(element: Byte): Int(source)
fun ShortArray.indexOf(element: Short): Int(source)
fun IntArray.indexOf(element: Int): Int(source)
fun LongArray.indexOf(element: Long): Int(source)
fun BooleanArray.indexOf(element: Boolean): Int(source)
fun CharArray.indexOf(element: Char): Int(source)

Returns first index of element, or -1 if the array does not contain element.

Since Kotlin

1.0
fun <T> Iterable<T>.indexOf(element: T): Int(source)

Returns first index of element, or -1 if the collection does not contain element.

Since Kotlin

1.0
fun <T> List<T>.indexOf(element: T): Int(source)

Returns first index of element, or -1 if the list does not contain element.

Since Kotlin

1.0
@ExperimentalUnsignedTypes
inline fun UIntArray.indexOf(element: UInt): Int(source)
@ExperimentalUnsignedTypes
inline fun ULongArray.indexOf(element: ULong): Int(source)
@ExperimentalUnsignedTypes
inline fun UByteArray.indexOf(element: UByte): Int(source)
@ExperimentalUnsignedTypes
inline fun UShortArray.indexOf(element: UShort): Int(source)

Returns first index of element, or -1 if the array does not contain element.

Since Kotlin

1.3
fun FloatArray.indexOf(element: Float): Int(source)
fun DoubleArray.indexOf(element: Double): Int(source)

Deprecated

Warning since 1.4

Error since 1.6

The function has unclear behavior when searching for NaN or zero values and will be removed soon. Use 'indexOfFirst { it == element }' instead to continue using this behavior, or '.asList().indexOf(element: T)' to get the same search behavior as in a list.

Replace with

indexOfFirst { it == element }
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Returns first index of element, or -1 if the array does not contain element.

Since Kotlin

1.0