Swift Comparison Operators

⚖️ What are Comparison Operators?

Comparison operators compare two values and return true or false. Use them to check if values are equal (==), not equal (!=), greater than (>), less than (<), or other relationships between values.


let age = 18
let isAdult = age >= 18    // true
let isChild = age < 13     // false

🟰

Equal (==)

Checks if two values are equal

let result = 5 == 5  // true
let same = "Hi" == "Hi" // true

≠

Not Equal (!=)

Checks if two values are different

let different = 5 != 3  // true
let notSame = "Hi" != "Bye" // true

>

Greater Than (>)

Checks if left value is greater

let bigger = 10 > 5   // true
let older = 25 > 18   // true

<

Less Than (<)

Checks if left value is smaller

let smaller = 3 < 8   // true
let younger = 15 < 21 // true

🔹 Basic Comparison Operations

Compare numbers, strings, and other values:

// Comparing numbers
let a = 10
let b = 5

let isEqual = a == b        // false
let isNotEqual = a != b     // true
let isGreater = a > b       // true
let isLess = a < b          // false
let isGreaterOrEqual = a >= b  // true
let isLessOrEqual = a <= b     // false

// Comparing strings
let name1 = "Alice"
let name2 = "Bob"
let name3 = "Alice"

let sameNames = name1 == name3    // true
let differentNames = name1 != name2  // true

print("10 > 5: \(isGreater)")
print("Alice == Alice: \(sameNames)")
print("Alice != Bob: \(differentNames)")

Output:

10 > 5: true

Alice == Alice: true

Alice != Bob: true

🔹 Greater Than or Equal (>=)

Check if a value is greater than or equal to another:

// Age verification
let userAge = 18
let minimumAge = 18
let canVote = userAge >= minimumAge  // true

// Grade checking
let score = 85
let passingGrade = 60
let hasPassed = score >= passingGrade  // true

// Price comparison
let budget = 100.0
let itemPrice = 99.99
let canAfford = budget >= itemPrice  // true

// String comparison (alphabetical order)
let word1 = "apple"
let word2 = "banana"
let isAlphabeticallyAfter = word1 >= word2  // false

print("Can vote (age \(userAge)): \(canVote)")
print("Passed with score \(score): \(hasPassed)")
print("Can afford $\(itemPrice): \(canAfford)")

Output:

Can vote (age 18): true

Passed with score 85: true

Can afford $99.99: true

🔹 Less Than or Equal (<=)

Check if a value is less than or equal to another:

// Speed limit checking
let currentSpeed = 55
let speedLimit = 60
let isWithinLimit = currentSpeed <= speedLimit  // true

// Capacity checking
let currentGuests = 45
let maxCapacity = 50
let hasSpace = currentGuests <= maxCapacity  // true

// Temperature checking
let temperature = 32
let freezingPoint = 32
let isFreezing = temperature <= freezingPoint  // true

// Discount eligibility
let purchaseAmount = 25.0
let discountThreshold = 50.0
let needsMoreForDiscount = purchaseAmount <= discountThreshold  // true

print("Within speed limit: \(isWithinLimit)")
print("Has space for more guests: \(hasSpace)")
print("Temperature is freezing: \(isFreezing)")

Output:

Within speed limit: true

Has space for more guests: true

Temperature is freezing: true

🔹 String Comparisons

Compare strings alphabetically and for equality:

// String equality
let greeting1 = "Hello"
let greeting2 = "Hello"
let greeting3 = "hello"

let exactMatch = greeting1 == greeting2      // true
let caseSensitive = greeting1 == greeting3   // false

// Alphabetical comparison
let firstName = "Alice"
let secondName = "Bob"
let thirdName = "Charlie"

let isAlphabeticallyFirst = firstName < secondName    // true
let isAlphabeticallyLast = thirdName > secondName     // true

// Case-insensitive comparison
let word1 = "Apple"
let word2 = "apple"
let caseInsensitiveEqual = word1.lowercased() == word2.lowercased()  // true

// String length comparison
let shortWord = "Hi"
let longWord = "Hello"
let isShorter = shortWord.count < longWord.count  // true

print("Exact match: \(exactMatch)")
print("Alice comes before Bob: \(isAlphabeticallyFirst)")
print("Case-insensitive equal: \(caseInsensitiveEqual)")
print("'Hi' is shorter than 'Hello': \(isShorter)")

Output:

Exact match: true

Alice comes before Bob: true

Case-insensitive equal: true

'Hi' is shorter than 'Hello': true

🔹 Using Comparisons in Conditions

Comparison operators are commonly used in if statements:

// Age-based decisions
let age = 16

if age >= 18 {
    print("You can vote!")
} else if age >= 16 {
    print("You can drive!")
} else {
    print("You're still young!")
}

// Grade evaluation
let testScore = 87

if testScore >= 90 {
    print("Grade: A")
} else if testScore >= 80 {
    print("Grade: B")
} else if testScore >= 70 {
    print("Grade: C")
} else {
    print("Grade: F")
}

// Password strength
let password = "mypassword123"
let minLength = 8

if password.count >= minLength {
    print("Password meets minimum length requirement")
} else {
    print("Password is too short")
}

Output:

You can drive!

Grade: B

Password meets minimum length requirement

Swift Comparison Operators

⚖️ What are Comparison Operators?