List Operations
If the list size is less than the specified index, an exception is thrown. However two functions can avoid such exception.
getOrElse():It calculate the default value to return if the index is absent in the collection.
getOrNull(): returns null as the default value.
val numbers = listOf(11, 22, 33, 44)
println(numbers.getOrNull(5)) // null
println(numbers.getOrElse(5, {it})) // 5
output:-
null
5
subList() function gives elements as a list from a give range.
val numbers = (10..23).toList()
println(numbers.subList(2, 4))
outuput:
[12, 13]
Position of an element can be get by indexOf() and lastIndexOf(). They return the first and the last position of an element . If elements is not found , both functions return -1.
val numbers = listOf(11, 22, 33, 44, 25, 56)
println(numbers.indexOf(3))
println(numbers.lastIndexOf(3))
ouput:-
-1
-1