Swiftly

Swift 5.1 references for busy coders

Logical operators (!, &&, ||)

Logical operators return a Bool to indicate whether or not a given statement is true. They are used heavily in if statements.

Logical NOT !

let name = "Tomoko"
print(name.isEmpty) // false
print(!name.isEmpty) // true
if !name.isEmpty { 
  print("name is not empty") // name is not empty
}

Logical AND &&

let loggedIn = true
let accountConfirmed = true
if loggedIn && accountConfirmed {
  print("The user is logged in and their account is confirmed.")
} else {
  print("Either not logged in, account not confirmed, or both.")
}
// The user is logged in, and their account is confirmed.

Logical OR ||

let loggedIn = true
let accountConfirmed = false
if loggedIn || accountConfirmed {
  print("Either logged in, account confirmed, or both.")
} else {
  print("Not logged in and account not confirmed.")
}
// Either logged in, account confirmed, or both.

Combining logical operators

Multiple logical operators can be combined to create longer expressions. Although operators && and || are left-associative, it is usually beneficial to include parentheses for readability.

let loggedIn = true
let accountConfirmed = true
let browsingAsGuest = false
if (loggedIn && accountConfirmed) || browsingAsGuest {
  print("The user is logged in with a confirmed account, or they are browsing as guest.")
}
// The user is logged in with a confirmed account, or they are browsing as guest.