If

In its simplest form, the if statement has a single if condition. It executes a set of statements only if that condition is true.

Basic Usage

var temperatureInFahrenheit = 30
if temperatureInFahrenheit <= 32 {
    print("It's very cold. Consider wearing a scarf.")
}
// Prints "It's very cold. Consider wearing a scarf."

If-Else

The if statement can provide an alternative set of statements, known as an else clause, for situations when the if condition is false:

temperatureInFahrenheit = 40
if temperatureInFahrenheit <= 32 {
    print("It's very cold. Consider wearing a scarf.")
} else {
    print("It's not that cold. Wear a t-shirt.")
}
// Prints "It's not that cold. Wear a t-shirt."

Chaining Multiple If-Else

You can chain multiple if statements together to consider additional clauses:

temperatureInFahrenheit = 90
if temperatureInFahrenheit <= 32 {
    print("It's very cold. Consider wearing a scarf.")
} else if temperatureInFahrenheit >= 86 {
    print("It's really warm. Don't forget to wear sunscreen.")
} else {
    print("It's not that cold. Wear a t-shirt.")
}
// Prints "It's really warm. Don't forget to wear sunscreen."