Swift Quick Syntax Reference

Chapter    7

Booleans

Boolean values can be either true or false. Booleans are used to help evaluate logical expressions. To declare a boolean value, you can assign a value immediately, or you can use the Bool data type to declare a boolean variable, as shown in Listing 7-1.

Listing 7-1. Declaring Booleans

var b1:Boollet b2 = false

In Chapter 6, you saw how to make a comparison between two strings to get a boolean value. You can store the results of an equality comparison like that in a boolean variable or constant, as shown in Listing 7-2.

Listing 7-2. Storing Boolean Results

let alphabet = "ABCDEFGHIJKLMNOP"let b4 = alphabet == "ABCDEFGHIJKLMNOP"

In Listing 7-2, the value of b4 is true because the two strings are the same; you can use this ...