is there a way to compare elements to each other i...

# getting-started

[hooliooo]

is there a way to compare elements to each other in a list? For example if I have:

listOf(A, B, C)

I want a way to compare A to B, B to C and A to C so they are all evaluated against each other

[steveme]

val list = listOf("a", "b", "c")
    list.forEach { fst -> list.forEach { snd -> println("$fst,$snd") } }

[Samme Kleijn]

What exactly do you want to have as a return value?

If you want to check if all values are equal you could just compare them to the first value for example..

val list = listOf(A, B, C)
val isEqual = list.all { it == list.first() }

But I doubt this is what you are looking for, could you give me an example of what you expect?

[Jakub Pi]

Comparing against the 1st element is a good solution if you want to make sure everything is equal. If you want to check whether elements next to each other are equal, consider using zipWithNext():

val list = listOf(A, B, C)
(list + list.first()).zipWithNext().map { (a, b) -> a == b }

This matches the original request, but if you have 4 elements you will only get 4 comparisons, not the cross product (e.g. A==C and B==D would never run)

[vineethraj49]

.distinct().size == 1?

[hooliooo]

I was able to do what I wanted with this

val elementsToDrop = myList.indexOf(zone)
val subsequence = myList.drop(elementsToDrop + 1)
if (subsequence.isEmpty()) return@map true
....