7.2 The Swift for-in Statement

The for-in loop is used to iterate over a sequence of items contained in a collection or number range and provides a simple to use looping option.

The syntax of the for-in loop is as follows:

for constant name in collection or range {

    // code to be executed

}

In this syntax, constant name is the name to be used for a constant that will contain the current item from the collection or range through which the loop is iterating. The code in the body of the loop will typically use this constant name as a reference to the current item in the loop cycle. The collection or range references the item through which the loop is iterating. This could, for example, be an array of string values, a range operator or even a string of characters (the topic of collections will be covered in greater detail within the chapter entitled “Working with Array and Dictionary Collections in Swift”).

Consider, for example,...