Hi all, Does anyone know how to do a partial match...

# multiplatform

[David Vega]

Hi all,
Does anyone know how to do a partial match of a string against a Regex in Kotlin multiplatform? Or said in other words, how can I know if a String could potentially match the Regex? similar to what can be accomplished with java.util.regex.Matcher.hitEnd()

As said, what I’m doing right now with java.util.regex.Matcher for Kotlin/JVM target is:

fun Regex.partialMatch(input: String): Boolean {
    val matcher: Matcher = toPattern().matcher(input)
    return if (matcher.matches()) { true } else { matcher.hitEnd() }
}

But I have tried several things and couldn’t find any way of of doing it on KMP.

For example: given this Regex of a date format (like ‘mm/dd/yyyy’ or ‘dd/mm/yyyy’):

val regex = Regex("[0-9]{2}/[0-9]{2}/[0-9]{4}")
regex.partialMatch("01") // true
regex.partialMatch("01/02") // true
regex.partialMatch("01/02/20") // true
regex.partialMatch("01/02/2023") // true
regex.partialMatch("000") // false

Any ideas?

[Adam S]

try regex.containsMatchIn("01")

https://kotlinlang.org/api/latest/jvm/stdlib/kotlin.text/-regex/contains-match-in.html

edit: oh, I looked properly at your examples now, you want some sort of String.startsWith(regex)?

[David Vega]

Yes, sort of

[Adam S]

try updating the regex so that everything after the first digit is optional. Then if a string doesn’t match matches, then it’s considered a partial match.