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ternary

The ternary operator (also known as the conditional operator) is a concise way to write simple conditional expressions. It uses the syntax condition ? valueIfTrue : valueIfFalse and returns one of two values based on a boolean condition.

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Basic Ternary Operator

Simple conditional value assignment: 
age = 20
status = age >= 18 ? "adult" : "minor"
println(status)  // "adult"

// Traditional if-else equivalent
if (age >= 18) {
    status = "adult"
} else {
    status = "minor"
}

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Ternary with Different Data Types

Return different types of values: 
// String values
isLoggedIn = true
greeting = isLoggedIn ? "Welcome back!" : "Please log in"

// Number values
quantity = 5
discount = quantity > 10 ? 0.1 : 0.05

// Boolean values
hasPermission = false
canAccess = hasPermission ? true : false

// Null values
user = getUser()
displayName = user != null ? user.name : "Guest"

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Ternary in Variable Assignment

Use ternary for conditional assignments: 
score = 85
grade = score >= 90 ? "A" : 
        score >= 80 ? "B" : 
        score >= 70 ? "C" : 
        score >= 60 ? "D" : "F"

// Price calculation
isPremium = true
basePrice = 100
finalPrice = isPremium ? basePrice * 0.9 : basePrice

// Default values
config = getConfig()
timeout = config != null ? config.timeout : 5000

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Ternary in Function Arguments

Pass conditional values to functions: 
level = 5
message = formatMessage(
    level > 3 ? "High priority" : "Normal priority",
    level > 7 ? "urgent" : "standard"
)

// Function calls
user = getCurrentUser()
logActivity(
    user != null ? user.id : "anonymous",
    user != null ? user.name : "Unknown User"
)

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Ternary in Return Statements

Return conditional values from functions: 
soul getAccessLevel(user) {
    return user.isAdmin ? "admin" : 
           user.isModerator ? "moderator" : "user"
}

soul calculateTax(amount, region) {
    return region == "NY" ? amount * 0.08 : 
           region == "CA" ? amount * 0.075 : 
           amount * 0.05
}

soul isValidEmail(email) {
    return email != null && email.contains("@") ? true : false
}

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Nested Ternary Operators

Chain multiple ternary operators: 
temperature = 75
weather = temperature > 80 ? "hot" : 
          temperature > 60 ? "warm" : 
          temperature > 40 ? "cool" : "cold"

// User role determination
user = getUser()
role = user == null ? "guest" : 
       user.isAdmin ? "admin" : 
       user.isModerator ? "moderator" : "user"

// Grade calculation
score = 88
letterGrade = score >= 90 ? "A" : 
              score >= 80 ? "B" : 
              score >= 70 ? "C" : 
              score >= 60 ? "D" : "F"

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Ternary with Object Properties

Use ternary for object property access: 
user = {
    "name": "Alice",
    "profile": {
        "avatar": "avatar.jpg"
    }
}

// Safe property access
userName = user != null ? user.name : "Unknown"
avatar = user != null && user.profile != null ? user.profile.avatar : "default.jpg"

// Object creation with ternary
person = {
    "name": name,
    "age": age != null ? age : 0,
    "isActive": isActive != null ? isActive : true
}

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Ternary in Array Operations

Use ternary with arrays: 
numbers = [1, 2, 3, 4, 5]
results = []

for (num in numbers) {
    // Add conditional values to array
    results.push(num > 3 ? "high" : "low")
}

// Array filtering with ternary
items = getItems()
filtered = items != null ? items.filter(isValid) : []

// Array access with ternary
firstItem = items.length() > 0 ? items[0] : null

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Ternary with Method Calls

Call different methods based on conditions: 
user = getCurrentUser()
message = user != null ? user.getWelcomeMessage() : getGuestMessage()

// Method chaining with ternary
result = data != null ? data.process().format() : getDefaultResult()

// Conditional method calls
logger = getLogger()
shouldLog = isDebugMode()
logMessage = shouldLog ? logger.debug("Debug info") : logger.info("Info")

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Ternary in String Operations

Use ternary for string manipulation: 
name = "alice"
displayName = name != null ? name.toUpperCase() : "UNKNOWN"

// String concatenation
firstName = "John"
lastName = "Doe"
fullName = firstName != null && lastName != null ? 
           firstName + " " + lastName : 
           "Name not available"

// String formatting
count = 5
message = "You have " + count + " " + (count == 1 ? "item" : "items")

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Ternary with Calculations

Use ternary in mathematical expressions: 
balance = 1000
withdrawAmount = 200
newBalance = balance >= withdrawAmount ? 
             balance - withdrawAmount : 
             balance

// Discount calculation
quantity = 15
unitPrice = 10
total = quantity * unitPrice
discount = quantity > 10 ? total * 0.1 : 0
finalTotal = total - discount

// Min/Max operations
a = 5
b = 8
maximum = a > b ? a : b
minimum = a < b ? a : b

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Ternary with Error Handling

Handle simple error cases: 
// Input validation
input = getUserInput()
processedInput = input != null && input != "" ? input.trim() : null

// Error messages
errorCode = getErrorCode()
errorMessage = errorCode == 404 ? "Not found" : 
               errorCode == 500 ? "Server error" : 
               "Unknown error"

// Safe operations
divisor = 5
result = divisor != 0 ? 100 / divisor : 0

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Ternary Performance Considerations

Optimize ternary usage: 
// Good - simple conditions
isActive = user != null ? user.isActive : false

// Avoid - complex expressions in ternary
// result = complexFunction() ? expensiveOperation() : anotherExpensiveOperation()

// Better - evaluate once
shouldProcess = complexFunction()
result = shouldProcess ? expensiveOperation() : anotherExpensiveOperation()

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Ternary vs If-Else

When to use ternary vs if-else: 
// Use ternary for simple value assignment
status = isOnline ? "online" : "offline"

// Use if-else for complex logic
if (user.isAdmin) {
    setupAdminDashboard()
    logAdminAccess()
    sendAdminNotification()
} else {
    setupUserDashboard()
    logUserAccess()
}

// Use ternary for inline conditions
message = "Hello " + (user != null ? user.name : "Guest") + "!"

// Use if-else for multiple statements
if (user != null) {
    welcomeUser(user)
    logUserActivity(user)
    updateLastSeen(user)
} else {
    showLoginForm()
    trackAnonymousVisit()
}

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Best Practices

  1. Keep it simple: Use ternary for simple conditions only
  2. Avoid deep nesting: More than 2-3 levels becomes hard to read
  3. Use parentheses: Clarify precedence with parentheses
  4. Consider readability: If-else might be clearer for complex logic
  5. Handle null values: Always consider null cases
// Good - simple and clear
age = 25
category = age >= 18 ? "adult" : "minor"

// Good - with parentheses for clarity
result = (score >= 90) ? "excellent" : (score >= 70) ? "good" : "needs improvement"

// Avoid - too complex
// complicated = condition1 ? (condition2 ? value1 : (condition3 ? value2 : value3)) : value4

// Better - break down complex ternary
if (condition1) {
    result = condition2 ? value1 : (condition3 ? value2 : value3)
} else {
    result = value4
}

// Good - safe null handling
user = getUser()
welcomeMessage = user != null ? "Hello " + user.name : "Welcome, Guest"

// Better - comprehensive null handling
user = getUser()
userName = (user != null && user.name != null) ? user.name : "Guest"
welcomeMessage = "Hello " + userName
The ternary operator is a powerful tool for writing concise conditional expressions. Use it for simple value assignments and inline conditions, but prefer if-else statements for complex logic and multiple statements.