Conditionals in

About Conditionals

Comparison operators

Comparison operators are used to compare values and return a true or false value. These operators require 2 values to be compared of the same type. If the values are not of the same type then the compiler will throw an error. Here is a list of the comparison operators and an example of when they give a true value:

If & Else statements

A conditional statement allows you to execute code based on a condition which is either true or false. The most basic conditional statement is an if statement which executes code when the condition is true. To declare an if statement you use the if keyword followed by the condition and then the code to execute in curly braces.

let wheelCount = 4
if wheelCount == 4 {
  print("Your vehicle is a car")
}
// Prints "Your vehicle is a car"

If can be combined with else to execute code when the condition is false. The else statement needs to be used with an if statement and cannot be used on its own. To declare an else statement you use the else keyword after an if statements curly braces, followed by the code to execute in curly braces.

let precipitationInMM = 0.5
if precipitationInMM > 0.5 {
  print("You will need an umbrella")
} else {
  print("You will not need an umbrella")
}
// Prints "You will not need an umbrella"

If statements can also be chained together using else if to check multiple conditions. It follows the same principle as defining an if statement but the keyword is else if instead of if. As If statement don't they need an else statement to be valid, but they can have one if needed.

let favoriteFruit = "Apple"

if favoriteFruit == "Banana" {
    print("Your favorite fruit is a banana")
} else if favoriteFruit == "Orange" {
    print("Your favorite fruit is an orange")
} else if favoriteFruit == "Apple" {
    print("Your favorite fruit is an apple")
} else {
    print("Your favorite fruit is not a banana, orange or apple")
}
// Prints "Your favorite fruit is an apple"

If expression

If statements can also be used as expressions to assign a value to a variable. The last statement in the if block is used as the value of the if expression. This can be useful when you want to assign a value to a variable based on a condition.

let CpuBits = 32
let largest = if CpuBits == 64 {
  "x86_64"
} else {
  "x86_32"
}

print(largest)
// Prints "x86_32"