Is there a better way to Count the Number of matching characters in a pair of strings in Kotlin

Question

fun compute(l: String, r: String): Int {
    var counter = 0
    for (i in l.indices) when {
        l[i]!=r[i] -> counter++
    }
    return counter
}

Is there an inbuilt function that can be used instead of looping over every character explicitly?

Assuming

1. strings have equal length
2. position of chars matters
3. comparison is case-sensitive

Answer 1

You can simply do count if the order does not matter:

return l.count { it in r }

However, if you want to check that the value and the index match, you cannot escape using index:

l.forEachIndexed { i, it -> 
    if(i < r.length && it == r[i]) counter++ 
}

UPD: Oh I just found out that there is commonPrefixWith

return l.commonPrefixWith(r).length