Kotlin - creating a mutable list with repeating elements
ListKotlinList Problem Overview
What would be an idiomatic way to create a mutable list of a given length n
with repeating elements of value v
(e.g listOf(4,4,4,4,4)
) as an expression.
I'm doing val list = listOf((0..n-1)).flatten().map{v}
but it can only create an immutable list.
List Solutions
Solution 1 - List
Use:
val list = MutableList(n) {index -> v}
or, since index
is unused, you could omit it:
val list = MutableList(n) { v }
Solution 2 - List
another way may be:
val list = generateSequence { v }.take(4).toMutableList()
This style is compatible with both MutableList and (Read Only) List
Solution 3 - List
If you want different objects you can use repeat
.
For example,
val list = mutableListOf<String>().apply {
repeat(2){ this.add(element = "YourObject($it)") }
}
Replace String with your object. Replace 2 with number of elements you want.