Swift Functional Programming - Second Edition

The join function

The join function takes an array of objects and joins them with a provided separator. The following example presents a simple version of join:

func join<Element: Equatable>(elements: [Element], separator: String) -> String {     return elements.reduce("") {         initial, element in         let aSeparator = (element == elements.last) ? "" : separator         return "\(initial)\(element)\(aSeparator)"     } } 

This function takes an array with a separator, joins elements in an array, and provides a single String. We can test it as follows:

let items = ["First", "Second", "Third"] let commaSeparatedItems = join(elements: items, separator: ", ") 

The result will be "First, Second, Third".