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stringfunctionkotlinextension-function

Capitalise every word in String with extension function

I want to make a extension function in Kotlin, that converts the first letter of each word of the string to upper case

the quick brown fox

to

The Quick Brown Fox

I tried using the capitalize() method. That only though capitalised the first letter of the String.

Solution

  • Since you know capitalize() all you need is to split the string with space as a delimeter to extract each word and apply capitalize() to each word. Then rejoin all the words.

    fun String.capitalizeWords(): String = split(" ").map { it.capitalize() }.joinToString(" ")

    use it: 

    val s = "the quick brown fox"
println(s.capitalizeWords())

    will print: 

    The Quick Brown Fox

    Note: this extension does not take in account other chars in the word which may or may not be capitalized but this does: 

    fun String.capitalizeWords(): String = split(" ").map { it.toLowerCase().capitalize() }.joinToString(" ")

    or shorter:

    @SuppressLint("DefaultLocale")
fun String.capitalizeWords(): String =
    split(" ").joinToString(" ") { it.toLowerCase().capitalize() }