Swift Programming: The Big Nerd Ranch Guide

Varying Variables and Printing to the Console

String is a type, and we say that the str variable is “an instance of the String type.” Types describe a particular structure for representing data. Swift has many types, which you will meet throughout this book. Each type has specific abilities – what the type can do with that data – and limitations – what it cannot do with the data. For example, the String type is designed to work with an ordered collection of characters and defines a number of functions to work with that ordered collection of characters.

Recall that str is a variable. That means you can change the variable’s value. Let’s append an exclamation point to the end of the string to make it a well-punctuated sentence. (Whenever ...