Swift Academy · Lesson

Bool Values and Expressions

Create and combine Boolean expressions.

The Bool Type

Swift has a dedicated type for truth values called Bool. A Bool can only ever hold one of two values: true or false.

You declare a Bool just like any other constant or variable.

let isLoggedIn = true
let hasError = false
print(isLoggedIn)
print(hasError)

Comparison operators like ==, !=, <, >, <= and >= all produce a Bool result.

The expression on the right is evaluated and stored as a true/false value.

let age = 20
let isAdult = age >= 18
let isTeen = age < 13
print(isAdult)
print(isTeen)