kotlin-stdlib/kotlin.text/Regex/find

find

expect fun find(input: CharSequence, startIndex: Int = 0): MatchResult?(source)(source)
actual fun find(input: CharSequence, startIndex: Int = 0): MatchResult?(source)(source)

Returns the first match of a regular expression in the input, beginning at the specified startIndex.

Since Kotlin

1.0

Return

An instance of MatchResult if match was found or null otherwise.

Parameters

startIndex

An index to start search with, by default 0. Must be not less than zero and not greater than input.length()

Throws

if startIndex is less than zero or greater than the length of the input char sequence.

Samples


fun main() { 
   //sampleStart 
   val inputString = "to be or not to be"
val regex = "to \\w{2}".toRegex()
// If there is matching string, then find method returns non-null MatchResult
val match = regex.find(inputString)!!
println(match.value) // to be
println(match.range) // 0..4

val nextMatch = match.next()!!
println(nextMatch.range) // 13..17

val regex2 = "this".toRegex()
// If there is no matching string, then find method returns null
println(regex2.find(inputString)) // null

val regex3 = regex
// to be or not to be
//              ^^^^^
// Because the search starts from the index 2, it finds the last "to be".
println(regex3.find(inputString, 2)!!.range) // 13..17 
   //sampleEnd
}