join
fun joinToString(separator: CharSequence = ", ", prefix: CharSequence = "", postfix: CharSequence = "", limit: Int = -1, truncated: CharSequence = "...", transform: (E) -> CharSequence? = null): String
Creates a String from the elements separated by separator and using prefix before and postfix after, if supplied.
When a non-negative value of limit is provided, a maximum of limit items are used to generate the string. If the collection holds more than limit items, the string is terminated with truncated.
transform may be supplied to convert each element to a custom String.