split and replace

Learn string processing with split and replace.

split and replace

split(delimiter) splits a String at the given delimiter and returns a List<String>. replace(old, new) swaps a piece with a new one.

val parts = "a,b,c".split(",")
println(parts)  // [a, b, c]
val fixed = "cat".replace("a", "o")
println(fixed)  // cot

The result of split is a list; each item is a separate String. replace changes all matches, not just the first.

Neither method mutates the original String; both return a new value.

Exercise Use split and replace

Write a fun main(). Assign "apple,bread" (with a comma) to val items. Print items.split(",") for the split list and items.replace("e", "E") for the swapped string on separate lines.

Show example solution

fun main() {
    val items = "apple,bread"
    println(items.split(","))
    println(items.replace("e", "E"))
}

replace and chaining

replace can also be chained. To make several swaps in order, call the methods back to back.

val s = "a-b-c"
val r = s.replace("-", " ").replace("a", "A")
println(r)  // A b c

First dashes become spaces, then a becomes A. Since each replace returns a new String, chaining works.

Order matters: replace("a", "A").replace("-", " ") makes a different intermediate value but the same result here.

Test yourself

Match the methods

split(",")

Splits at comma
replace("a", "e")

Turns a to e
split(" ")

Splits at space
parts[0]

First item
What does "a,b,c".split(",") return?
- A String
- A list of three Strings
- Three chars
- Error
Show answer

A list of three Strings — split returns a List<String>; here it has three items.

Complete the replace call

val fixed = s.____("a", "e")

Show answer

val fixed = s.replace("a", "e")

Next lesson: Summary - Strings

We Are Enhancing Your Experience

Cookie Preferences

Strictly Necessary Cookies

Analytical Cookies