Understanding Assignment Operators

Introduction to Assignment Operators

Assignment operators in Swift are special symbols used to assign or update values of variables or constants. These operators ensure that the right-hand side (value) is assigned to the left-hand side (variable or constant). The data type on both sides must match; otherwise, an error occurs. Assignment operators in Swift follow right-to-left associativity.

Swift supports two main types of assignment operators:

1. Simple Assignment Operator: Assigns a value to a variable.

2. Compound Assignment Operators: Combines the assignment operator (=) with arithmetic or bitwise operations.

List of Assignment Operators in Swift

Name	Example
Assignment	var x = 10
Add and Assignment	A += B → A = A + B
Subtract and Assignment	A -= B → A = A - B
Multiply and Assignment	A = B → A = A B
Divide and Assignment	A /= B → A = A / B
Modulo and Assignment	A %= B → A = A % B
Bitwise AND and Assignment	A &= B → A = A & B
Bitwise Inclusive OR and Assignment	A \|= B → A = A \| B
Bitwise Exclusive OR and Assignment	A ^= B → A = A ^ B
Left Shift and Assignment	A <<= B → A = A << B
Right Shift and Assignment	A >>= B → A = A >> B

Simple Assignment Operator (=)

The = operator assigns a value to a variable or constant.

Syntax

var number 10

Example

import Foundation

let myString: String = "SwiftProgramming"
print("String =", myString)

Output

String = SwiftProgramming

Add and Assignment Operator (+=)

The += operator adds the right-hand value to the left-hand value and assigns the result to the left-hand variable.

Syntax

X +=Y

Example

import Foundation

var num1 = 15
var num2 = 25
num1 += num2

print("Sum =", num1)

Output

Sum = 40

Subtract and Assignment Operator (-=)

The -= operator subtracts the right-hand value from the left-hand value and assigns the result to the left-hand variable.

import Foundation

var num1 = 50
var num2 = 30
num1 -= num2

print("Result =", num1)

Output

Result = 20

Multiply and Assignment Operator (*=)

The *= operator multiplies the left operand by the right operand and assigns the result to the left operand.

Example

import Foundation

var num1 = 6
var num2 = 7
num1 *= num2

print("Result =", num1)

Output

Result = 42

Divide and Assignment Operator (/=)

The /= operator divides the left operand by the right operand and assigns the result to the left operand.

Example

import Foundation

var num1 = 100
var num2 = 4
num1 /= num2

print("Result =", num1)

Output

Result = 25

Modulo and Assignment Operator (%=)

The %= operator calculates the remainder when dividing the left operand by the right operand and assigns the result to the left operand.

Example

import Foundation

var num1 = 29
var num2 = 4
num1 %= num2

print("Result =", num1)

Output

Result = 1

Bitwise AND and Assignment Operator (&=)

The &= operator performs a bitwise AND operation and assigns the result to the left operand.

Example

import Foundation

var num1: UInt8 = 0b10101010
let num2: UInt8 = 0b11001100
num1 &= num2

print("Result =", String(num1, radix: 2))

Output

Result = 10001000

Bitwise Inclusive OR and Assignment Operator (|=)

The |= operator performs a bitwise OR operation and assigns the result to the left operand.

Example

import Foundation

var num1: UInt8 = 0b10101010
let num2: UInt8 = 0b11001100
num1 |= num2

print("Result =", String(num1, radix: 2))

Output

Result = 11101110

Left Shift and Assignment Operator (<<=)

The <<= operator shifts bits to the left and assigns the result to the left operand.

Example

import Foundation

var number: UInt8 = 0b00010101
number <<= 2

print("Result =", String(number, radix: 2))

Output

Result = 1010100

Right Shift and Assignment Operator (>>=)

The >>= operator shifts bits to the right and assigns the result to the left operand.

Example

import Foundation

var number: UInt8 = 0b10101000
number >>= 3

print("Result =", String(number, radix: 2))

Output

Result = 10101