Hi, hope this is the right place. I am trying to loop through a list of Strings so that I can create...

# getting-started

[Nat Strangerweather]

Hi, hope this is the right place. I am trying to loop through a list of Strings so that I can create an array called Letter which is made of a String and an Int. The problem is that whatever I do, I only ever get the last value of my list of Strings. What could I be doing wrong?

fun savedData(): Array<Letter> {
        val arr = mutableStateOf(boardLetters)
        if (savedValues != null) {
            for (item in savedLetters!!) {
                arr.value = Array(28) {
                    Letter(item, 0)
                }
            }
        }
        return arr.value
    }

For info: boardLetters is this: boardLetters: Array<Letter> Thanks for any help.

[Luke]

The problem is that you assign arr.value to an array for each savedLetters, so you replace the array each iteration, keeping the last in the end

[Luke]

I'm guessing what you want is something like:

fun savedData(): Array<Letter> {
    return savedValues?.map { Letter(it, 0) }
        ?.toTypedArray()
        ?: arrayOf()
}

[Nat Strangerweather]

Thank you so much! 👍

[Nat Strangerweather]

I also have a list of savedValues for each savedLetters. How can I add them instead of the 0?

[Luke]

savedValues is a list with corresponding index, a map, or something else?

[nkiesel]

fun savedData(savedLetters: List<String>, savedValues: List<Letter>): List<Letter> {
    return savedLetters.map { l -> Letter(l, savedValues.find { it.letter == l }?.value ?: 0) }
}

[nkiesel]

or - better if savedValues can become long -

fun savedData(savedLetters: List<String>, savedValues: List<Letter>): List<Letter> {
    val m = savedValues.associateBy(Letter::letter)
    return savedLetters.map { l -> m.getOrDefault(l, Letter(l, 0)) }
}

[Nat Strangerweather]

Thanks a lot, I'm in a call but will check it out after. Cheers! 🙂

[nkiesel]

fun savedData(savedLetters: List<String>, savedValues: List<Letter>): List<Letter> {
    return with(savedValues.associateBy(Letter::letter)) { savedLetters.map { get(it) ?: Letter(it, 0) } }
}

if you like one-liners...

[nkiesel]

note that this assumes that Letter is immutable. If that is not the case, you must return new letters:

fun savedData(savedLetters: List<String>, savedValues: List<Letter>): List<Letter> {
    return with(savedValues.associateBy(Letter::letter)) { savedLetters.map { Letter(it, get(it)?.value ?: 0) } }
}

[Nat Strangerweather]

Thanks again, that very helpful!