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kotlinlang

hello, so i was trying to find a more elegant way to write the following: `selectedChoices.mapIndexed { index, isSelected -&gt; if (isSelected) index else -1 }.filter { it != -1 }`. Is there a prettier way to write this ? :slightly_smiling_face: In short what I want to do is get the indexes from `selectedChoices`, which is a BooleanArray, where the value is `true` and then map those indexes in something different, hence the `.filter { it != -1}` (also not sure if I am on the right channel)

pavlospt: 
```
booleanArrayOf(true, true, false, true).withIndex().filter { it.value }.map { it.index }
booleanArrayOf(true, true, false, true).toList().mapIndexedNotNull { index, v -&gt; if (v) index else null }
```

I'd go with ```selectedChoices.mapIndexedNotNull { index, isSelected -&gt; index.takeIf { isSelected } }```

Hmm that one seems pretty nice as well! Thanks!