parse string to an array in Kotlin

Question

How can I convert a string to an array of strings in Kotlin? To demonstrate, I have this:

val input_string = "[Hello, World]"

I would like to convert it to ["Hello", "World"].

How about [parsing it as JSON](https://stackoverflow.com/questions/41928803/how-to-parse-json-in-kotlin)? — Ruud Helderman, Feb 08 '22 at 10:38

score 4 · Accepted Answer · answered Feb 08 '22 at 10:36

4

Assuming that the array elements do not contain commas, you can do:

someString.removeSurrounding("[", "]")
    .takeIf(String::isNotEmpty) // this handles the case of "[]"
    ?.split(", ") 
    ?: emptyList() // in the case of "[]"

This will give you a List<String>. If you want an Array<String>:

someString.removeSurrounding("[", "]")
    .takeIf(String::isNotEmpty)
    ?.split(", ")
    ?.toTypedArray()
    ?: emptyArray()

answered Feb 08 '22 at 10:36

Sweeper

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Are you sure you need the step with _takeIf_ (and _?: emptyList()_)? – lukas.j Feb 08 '22 at 10:47
@lukas.j Yes. For the input string `[]`, you want an empty list/array, not a list with one empty string in it, right? – Sweeper Feb 08 '22 at 10:48
Of course, you're right (almost every time I come back to Kotlin I stumble across the _split_ specialities...). – lukas.j Feb 08 '22 at 10:49

score 1 · Answer 2 · answered Feb 08 '22 at 10:56

1

Assuming the strings only consist of letters and/or numbers you could also do it like this

val input_string = "[Hello, World]"
val list = Regex("\\w+").findAll(input_string).toList().map { it.value }

answered Feb 08 '22 at 10:56

Ivo

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parse string to an array in Kotlin

2 Answers2