Print Multi-dimenstional Array in Kotlin?

Given the array below what is the simplest way to print it? Looping is one option but is there any other simpler option?

val array = arrayOf(arrayOf(1, 2),
arrayOf(3, 4),
arrayOf(5, 6, 7))


3 Answers
3

1. Using standard library

val array = arrayOf(arrayOf(1, 2),
arrayOf(3, 4),
arrayOf(5, 6, 7))

print(Arrays.deepToString(array))


2. Using for loop

fun <T> print2DArray(twoDArray: Array<Array<T>>) {
for (i in 0 until twoDArray.size) {
for (j in 0 until twoDArray[i].size) {
print(twoDArray[i][j])
if (j != twoDArray[i].size - 1) print(" ")
}
if (i != twoDArray.size - 1) println()
}
}


val array = arrayOf(arrayOf(1, 2),
arrayOf(3, 4),
arrayOf(5, 6, 7))

print2DArray(array)


There is built-in functionality for this:

val array = arrayOf(arrayOf(1, 2),
arrayOf(3, 4),
arrayOf(5, 6, 7))

println(array.joinToString(prefix = "[", postfix = "]") {
it.joinToString(prefix = "[", postfix = "]")
})


That depends on the way you want to show it.

fun Array.contentDeepToString: String


Returns a string representation of the contents of this array as if it is a List. Nested arrays are treated as lists too.
If any of arrays contains itself on any nesting level that reference is rendered as "[...]" to prevent recursion.

Note this is an inlined function using Arrays.deepToString(array) under the hood.

Arrays.deepToString(array)

Then using array.contentDeepToString() you get in the output this string:

array.contentDeepToString()

[[1, 2], [3, 4], [5, 6, 7]]

I mostly use Array.joinToString, its allow to join the array using a given separator and applying a transformation to each element. From the doc:

Array.joinToString

Creates a string from all the elements separated using [separator] and using the given [prefix] and [postfix] if supplied. If the collection could be huge, you can specify a non-negative value of [limit], in which case only the first [limit]
elements will be appended, followed by the [truncated] string (which defaults to "...")

In your case as each item of your array is a subarray, you have to apply a transformation for them also using

array.joinToString("n") { subarray ->
subarray.joinToString()
}


This give you an output as:

1, 2
3, 4
5, 6, 7

You can play with separator, prefix, postfix, and transformation parameters to get your wanted format.

contentDeepToString

joinToString

joinToString

Iterable

Sequence

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