Read and write custom subscripts
Let's see how to define a subscript that is used to read and write to a backend array. Reading and writing to a backend storage class is one of the most common uses of custom subscripts, but, as we will see in this chapter, we do not need to have a backend storage class. The following code is a subscript to read and write an array:
class MyNames { private var names:[String] = ["Jon", "Kim", "Kailey", "Kara"] subscript(index: Int) -> String { get { return names[index] } set { names[index] = newValue } } }
As we can see, the syntax is similar to how we can define properties within a class using the get
and set
keywords. The difference is that we declare the subscript using the subscript
keyword. We then specify one ...
Get Swift: Developing iOS Applications now with the O’Reilly learning platform.
O’Reilly members experience books, live events, courses curated by job role, and more from O’Reilly and nearly 200 top publishers.