Kotlin: How to format a list of LocalDateTime to String?

Issue

I have succedded to format LocalDateTime to String but now how can I do the same for a list ?

The first function works but the second one doesn't work.

Here my class

class DateFormat {

    companion object {
    
        const val PATTERN = "dd-MM-yyyy HH:mm:ss"
    
        fun format(date: LocalDateTime): String {
            val formatter = DateTimeFormatter.ofPattern(PATTERN)
            return date.format(formatter)
        }
    
        fun formatList(date: List<LocalDateTime>): String {
            val formatter = DateTimeFormatter.ofPattern(PATTERN)
            return date.forEach {
                format(formatter)
            }
        }
    }
}

Solution

to return a list of strings you could do this

fun formatList(date: List<LocalDateTime>): List<String> {
    val formatter = DateTimeFormatter.ofPattern(PATTERN)
    return date.map { it.format(formatter) }
}

or even shorter by referring to your other function like this:

fun formatList(date: List<LocalDateTime>): List<String> {
    return date.map { format(it)}
}

or even this to make it super short

fun formatList(date: List<LocalDateTime>) = date.map { format(it)}

Edit: realized you could even write this

fun formatList(date: List<LocalDateTime>) = date.map(::format)

Answered By - Ivo Beckers