Hmhm, struggling to find a good name for a extension function that returns true when two lists have ...

# codereview

[Daniel]

Hmhm, struggling to find a good name for a extension function that returns true when two lists have identical content (same references).

fun <T> List<T>.isSameAs(other: List<T>): Boolean {
        if(size != other.size) return false

        forEachIndexed { index, element ->
            if(element !== other[index]) return false
        }

        return true
    }

Does anybody have an idea? Also maybe there might be a better way to check this?

[Shawn]

I think that’s about as good as you can get it really - assuming order matters and hashCode() isn’t good enough for equality. You might consider adding an if (this === other) return true but it’s not strictly necessary

[Shawn]

also maybe just call it identicalTo()

[Shawn]

as a personal point of style I don’t really like forEach/forEachIndexed for side-effect-ey operations that aren’t at the end of a call chain but that’s a nit more than anything in this case

[bitnot]

is it different from contentEquals?
https://kotlinlang.org/api/latest/jvm/stdlib/kotlin.collections/content-equals.html

[Mike]

contentEquals is for Array, not List. Otherwise, I think they're the same, and you have just provided a meaningful name.

[Shawn]

contentEquals compares with `==/.equals()`, the requirement was identity equality of the elements ===

[Shawn]

I think this is about as concise as I could get it

infix fun <E> List<E>.identicalTo(other: List<E>): Boolean = when {
  this === other -> true
  size != other.size -> false
  else -> withIndex().all { (index, value) ->
    value === other[index]
  }
}

or this very mildly cursed looking thing

infix fun <E> List<E>.identicalTo(other: List<E>): Boolean =
    other === this
        || other.size == size
        && withIndex().all { (index, value) ->
      value == other[index]
    }

[Daniel]

Thank you all! Curious usecase and understandable, that this isn't in the standard lib

[Daniel]

The withIndex is smart!