Swift If Else

Basic if Statements

An if statement evaluates a Boolean expression and runs its body only when that expression is true. Unlike some languages, Swift requires the condition to be a genuine Bool — you cannot use an integer like 0 or 1 as a stand-in for true or false, which eliminates an entire class of accidental bugs.

let temperature = 30

if temperature > 25 {
    print("It's a hot day")
}
// Prints: It's a hot day

Adding else and else if

An else clause provides a fallback branch that runs when the if condition is false. When you have several mutually exclusive conditions to check in sequence, else if chains them together, and Swift evaluates each condition top to bottom, running only the first branch whose condition is true.

let score = 82

if score >= 90 {
    print("Grade: A")
} else if score >= 75 {
    print("Grade: B")
} else if score >= 60 {
    print("Grade: C")
} else {
    print("Grade: F")
}
// Prints: Grade: B

Combining Conditions

Logical operators let you combine multiple Boolean expressions into a single condition. The && (AND) operator requires both sides to be true, || (OR) requires at least one side to be true, and ! (NOT) inverts a Boolean value. Swift short-circuits && and ||, meaning the right-hand side is only evaluated if it is actually needed.

• && — true only when both operands are true
• || — true when at least one operand is true
• ! — inverts a Bool, turning true into false and vice versa
• Comparison operators (==, !=, <, >, <=, >=) produce the Bool values conditions are built from
• Parentheses group sub-conditions to control evaluation order explicitly

let age = 20
let hasID = true

if age >= 18 && hasID {
    print("Entry allowed")
} else {
    print("Entry denied")
}

let isWeekend = false
let isHoliday = true

if isWeekend || isHoliday {
    print("No work today")
}

if as an Expression

Traditionally if is a statement in Swift, but you can still capture a value from a branching decision using the ternary conditional operator condition ? valueIfTrue : valueIfFalse, which is a compact single-line alternative to a full if-else block when both branches simply produce a value.

let count = 3
let label = count == 1 ? "item" : "items"
print("\(count) \(label)") // 3 items

let a = 7
let b = 12
let larger = a > b ? a : b
print(larger) // 12