Purpose of Array “Join” function in Swift

Here is a somewhat useful example with strings:

Swift 3.0

let joiner = ":"
let elements = ["one", "two", "three"]
let joinedStrings = elements.joined(separator: joiner)
print("joinedStrings: \(joinedStrings)")

output:

joinedStrings: one:two:three

Swift 2.0

var joiner = ":"
var elements = ["one", "two", "three"]
var joinedStrings = elements.joinWithSeparator(joiner)
print("joinedStrings: \(joinedStrings)")

output:

joinedStrings: one:two:three

Swift 1.2:

var joiner = ":"
var elements = ["one", "two", "three"]
var joinedStrings = joiner.join(elements)
println("joinedStrings: \(joinedStrings)")

The same thing in Obj-C for comparison:

NSString *joiner = @":";
NSArray *elements = @[@"one", @"two", @"three"];
NSString *joinedStrings = [elements componentsJoinedByString:joiner];
NSLog(@"joinedStrings: %@", joinedStrings);

output:

joinedStrings: one:two:three