Swift Assignment Operators

Assigning and modifying values in Swift

📝 What are Assignment Operators?

Assignment operators in Swift are used to assign values to variables and constants. They include basic assignment (=) and compound assignment operators that combine assignment with arithmetic operations for cleaner, more efficient code. 


// Basic assignment
var score = 100
var name = "Swift"

Types of Assignment Operators

=

Basic Assignment

Assigns a value to a variable 

var x = 10
let y = "Hello"
+=

Addition Assignment

Adds and assigns the result 

var a = 5
a += 3  // a = 8
-=

Subtraction Assignment

Subtracts and assigns the result 

var b = 10
b -= 4  // b = 6
*=

Multiplication Assignment

Multiplies and assigns the result 

var c = 3
c *= 4  // c = 12

🔹 Basic Assignment Operator

The basic assignment operator (=) assigns the value on the right to the variable on the left: 

// Assigning values
var playerName = "Alice"
var playerScore = 1500
var isActive = true

// Assigning one variable to another
var highScore = playerScore
print(highScore)  // Output: 1500

Output:

1500

🔹 Compound Assignment Operators

Compound assignment operators combine assignment with arithmetic operations:

🔸 Addition Assignment (+=) 

var points = 100
points += 50    // Same as: points = points + 50
print(points)   // Output: 150

var message = "Hello"
message += " World"  // String concatenation
print(message)       // Output: Hello World

Output:

150
Hello World

🔸 Subtraction Assignment (-=) 

var health = 100
health -= 25    // Same as: health = health - 25
print(health)   // Output: 75

Output:

75

🔸 Multiplication Assignment (*=) 

var multiplier = 3
multiplier *= 4    // Same as: multiplier = multiplier * 4
print(multiplier)  // Output: 12

Output:

12

🔸 Division Assignment (/=) 

var total = 20.0
total /= 4.0      // Same as: total = total / 4.0
print(total)      // Output: 5.0

Output:

5.0

🔹 Remainder Assignment (%=)

The remainder assignment operator finds the remainder and assigns it: 

var number = 17
number %= 5       // Same as: number = number % 5
print(number)     // Output: 2 (17 divided by 5 leaves remainder 2)

Output:

2

🔹 Practical Examples

Real-world usage of assignment operators: 

// Game scoring system
var playerScore = 0
playerScore += 100    // Player gets 100 points
playerScore += 50     // Player gets 50 more points
playerScore -= 25     // Player loses 25 points
print("Final Score: \(playerScore)")  // Output: Final Score: 125

// Shopping cart calculation
var cartTotal = 29.99
cartTotal += 15.50    // Add another item
cartTotal *= 1.08     // Add 8% tax
print("Total with tax: $\(cartTotal)")  // Output: Total with tax: $49.1292

Output:

Final Score: 125
Total with tax: $49.1292

🧠 Test Your Knowledge

What will be the value of x after: var x = 10; x += 5; x *= 2?