Split space from string not working in Kotlin

Here's an issue between the Java and Kotlin implementation of String.split.

While the Java implementation does accept a regex string, the Kotlin one does not. For it to work, you need to provide an actual Regex object.

To do so, you would update your code as follows:

value.split("\\s".toRegex())[0]

Also, as @Thomas suggested, you can just use the regular space character to split your string with:

value.split(" ")[0]

Final point, if you're only using the first element of the split list, you might want to consider using first() instead of [0] - for better readability - and setting the limit parameter to 2 - for better performance.

You need to use :

.toRegex()

fun main(args: Array<String>) {
        val str = "Kotlin com"

        val separate1 = str.split("\\s".toRegex())[0]
        println(separate1) // ------------------> Kotlin
}

OR

You can also use .split(" ")[0] to achieve result. Like

fun main(args: Array<String>) {
            val str = "Kotlin com"

            val separate1 = str.split(" ")[0]
            println(separate1) // ----------> Kotlin
}

String#split (actually CharSequence#split) can take either a regular expression, or just a string which is interpreted literally. So:

value.split(" ")[0]

does what you want.

If you're only using the first element, it's more efficient to also pass limit = 2. Or, even better, use substringBefore.