How to compare two arrays in Kotlin?

arrays equals kotlin

In Kotlin 1.1 you can use contentEquals and contentDeepEquals to compare two arrays for structural equality. e.g.:

a contentEquals b // trueb contentEquals c // false

In Kotlin 1.0 there are no "built-in functions to the Kotlin std-lib that tests two arrays for (value) equality for each element."

"Arrays are always compared using equals(), as all other objects" (Feedback Request: Limitations on Data Classes | Kotlin Blog).

So a.equals(b) will only return true if a and b reference the same array.

You can, however, create your own "optionals"-friendly methods using extension functions. e.g.:

fun Array<*>.equalsArray(other: Array<*>) = Arrays.equals(this, other)fun Array<*>.deepEqualsArray(other: Array<*>) = Arrays.deepEquals(this, other)

arrays equals kotlin

Kotlin 1.1 introduced extensions for comparing arrays by content:contentEquals and contentDeepEquals.

These extensions are infix, so you can use them the following way:

val areEqual = arr1 contentEquals arr2

arrays equals kotlin

And if you want to compare contents of two Collections ignoring the order you can add this simple extension:

infix fun <T> Collection<T>.sameContentWith(collection: Collection<T>?)    = collection?.let { this.size == it.size && this.containsAll(it) }

...and use it like this:

a = mutableListOf<String>()b = mutableListOf<String>()isListsHasSameContent = a sameContentWith b

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