Kotlin String to Int array

Question

I´m looking for the most efficient way to convert an String like

"[1,2,3,4,5]"

to an array of Int [1,2,3,4,5] in Kotlin

Duplicate of https://stackoverflow.com/questions/45823162/how-to-convert-string-array-to-int-array-in-kotlin — Julian Rubin, Nov 19 '17 at 23:38
Hi Julian, the question you suggest as duplicated refers to an array of Strings, and clearly is not the case here. This question is about only one String, containing and array of Int — heisen, Nov 19 '17 at 23:45
For better understanding, here is a question asking for the same case, but in Java https://stackoverflow.com/questions/7646392/convert-string-to-int-array-in-java — heisen, Nov 19 '17 at 23:49
[This answer](https://stackoverflow.com/a/25839398/3195526) to the above question is pretty easy to translate to idionmatic Kotlin. Or use klaxon or JSONObject, for an answer like @Slai's — Paul Hicks, Nov 19 '17 at 23:59

heisen · Accepted Answer · 2017-11-20T00:59:39.620

20

Fortunately I've been able to make it work, so I'll leave it here for future reference

val result = "[1,2,3,4,5]".removeSurrounding("[", "]").split(",").map { it.toInt() }

Many thanks to all!

edited Nov 20 '17 at 00:59

answered Nov 20 '17 at 00:22

heisen

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Competitive programming? Either way, thanks. – Nate T Feb 22 '22 at 14:16

score 3 · Answer 2 · answered Sep 27 '19 at 10:35

3

When user convert list to string and again need that string to list. Due to space between integer app crashes with NumberFormatException for that just remove unnecessary space.

val result = "[1, 2, 3, 4, 5]".removeSurrounding("[","]").replace(" ","").split(",").map { it.toInt() }

answered Sep 27 '19 at 10:35

Rahul Khatri

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simply call it.trim().toInt() to remove empty spaces – Richard Muvirimi Oct 13 '20 at 13:07
@RichardMuvirimi Can one not specify 2 characters in split? As in `List.split(",\ ")` – Nate T Feb 22 '22 at 22:13
1

@NateT use regex https://kotlinlang.org/api/latest/jvm/stdlib/kotlin.text/split.html – Richard Muvirimi Feb 27 '22 at 09:11

score 0 · Answer 3 · answered Nov 19 '17 at 23:45

Try with toCharArray() cutting first and last ( '[' and ']' )

inline fun String.toCharArray(
    destination: CharArray, 
    destinationOffset: Int = 0, 
    startIndex: Int = 1, 
    endIndex: Int = length -1
): CharArray (source)

You can then manually copy converted values from char to int in a new array

See more in the kotlin webpage

score 0 · Answer 4 · answered Mar 12 '21 at 14:37

0

Also another way to achieve this:

"[1,2,3,4,5]".replace(Regex("""[\[,\]]"""), "").map { it - '0' }

answered Mar 12 '21 at 14:37

gce

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Kotlin String to Int array

4 Answers4