Is there a Kotlin function to split a string into an array?

Question

I have tried str.split(,).toTypedArray(), but it doesn’t make an array.

var tasks = ""

tasks.plus(",").plus("Hey")
tasks.plus(",").plus("Hey")
tasks.plus(",").plus("Hey")
tasks.plus(",").plus("Hey")

val array = tasks.split(",").toTypedArray()

array.forEach {println(it)}

the output returns nothing so far.

Is there a way to split the string where the input is:

"xyx yxy xyx" and get an output: ["xyx","yxy","xyx"]

Yes

Benjamin Urquhart
– Benjamin Urquhart

2019-07-31 18:43:30 +00:00
Commented Jul 31, 2019 at 18:43 — Benjamin Urquhart
– Benjamin Urquhart, Commented Jul 31, 2019 at 18:43

forpas · Accepted Answer · 2019-07-31 18:27:57Z

1

In Kotlin strings are immutable, so don't expect this:

tasks.plus(",").plus("Hey")

to append anything to tasks.
The operator function plus() returns the string that you want to append but does not also append it.
You must do it like this:

tasks = tasks.plus(",").plus("Hey")
tasks = tasks.plus(",").plus("Hey")
tasks = tasks.plus(",").plus("Hey")
tasks = tasks.plus(",").plus("Hey")

and then with:

val array = tasks.split(",").toTypedArray()
array.forEach { println(it) }

the result that will be printed is:

<empty line here because of the 1st comma>
Hey
Hey
Hey
Hey

answered Jul 31, 2019 at 18:27

forpas

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3 Comments

gidds Over a year ago

Though if you're going to construct a string, calling plus() is a very inefficient way of doing it. (It will create ever-longer temporary copies.) Far better to append everything to a StringBuilder, and then convert that to a String at the end.

forpas Over a year ago

@gidds I aggree with you. My answer is not about the efficiency of the method but why it does not work as the OP says.

gidds Over a year ago

Oh, I wasn't criticising your answer, which is good! I was just adding a further point about the code (as it's something people tend to get wrong).

ThS · Accepted Answer · 2019-07-31 18:21:49Z

0

You can split the string based on the space char using split which returns a List then call toTypedArray to produce an array from that list.

val arr = "xyx yxy xyx".split(" ").toTypedArray();

Here's an online Demo.

answered Jul 31, 2019 at 18:21

ThS

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Comments

David Soroko · Accepted Answer · 2019-07-31 21:46:56Z

0

tasks in your code remains empty, the following works as expected:

var tasks = ""

tasks = tasks.plus(",").plus("Hey")
.plus(",").plus("Hey")
.plus(",").plus("Hey")
.plus(",").plus("Hey")

val array = tasks.split(",").toTypedArray()

You can actually have have tasks as val like so:

val tasks = ",".plus("Hey")
.plus(",").plus("Hey")
.plus(",").plus("Hey")
.plus(",").plus("Hey")

or even

val tasks = ",Hey,Hey,Hey,Hey"

and also

",Hey,Hey,Hey,Hey".split(",").forEach { println(it) }

edited Jul 31, 2019 at 21:46

answered Jul 31, 2019 at 18:32

David Soroko

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