kotlin, how to check if a index is in range

user_2987953 0
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Having a case that a map is passed in with data like

Map<Pair<Int, Int>), String>

Pair<Int, Int>) // zero based star index, inclusive end index
to
displayString

when doing the process, need to pick up proper displayString for current position, like 

var index = 0
for (data in dataList) {
   /*
   if the current index is within one of the pair<int, int> 
   then use the mapped displayString
   */
   index++
}

what is best way to do in kotlin?

kotlin
1 Answers

Not sure if this is what you meant, but possibly something like this:

var index = 0
for (data in dataList) {
   /*
   if the current index is within one of the pair<int, int> 
   then use the mapped displayString
   */
   val currentPair = data.key
   if ((currentPair.first .. currentPair.second).contains(index)) {
       // do something
   }

   index++
}

Though if you meant you wanted a getter to get the first pair from the map which contains an int the perhaps you wanted something like this:

fun getByIndex(dataList: Map<Pair<Int,Int>, String>, index: Int): String? {
   return dataList.firstOrNull { 
       (it.key.first .. it.key.second).contains(index) 
   } 
}

Use until instead of .. to have exclusive end index

user_97794710
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