🔄 PHP Swapping Variables – Exchange Values in PHP Efficiently

Learn how to swap two variables in PHP using traditional and modern methods for cleaner, readable, and efficient code logic.

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🧲 Introduction – Why Swap Variables in PHP?

Swapping variables is a basic operation in programming — commonly used in sorting algorithms, game logic, or data manipulation. PHP provides multiple ways to swap two variables without using any special library.

🎯 In this guide, you’ll learn:

• How to swap variables using temporary variables
• How to swap variables using list destructuring (PHP 7+)
• When and why swapping is useful
• Best practices for clean and readable swaps

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🔄 Traditional Variable Swapping (Using a Temporary Variable)

$a = 10;
$b = 20;

$temp = $a;
$a = $b;
$b = $temp;

echo "a = $a, b = $b"; // Output: a = 20, b = 10

✅ This method works in all PHP versions
📌 Simple and easy to understand

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🆕 Modern Swapping (PHP 7+ Destructuring)

$a = 5;
$b = 8;

[$a, $b] = [$b, $a];

echo "a = $a, b = $b"; // Output: a = 8, b = 5

✅ Clean, concise, and avoids temporary variables
📌 Available in PHP 7.1+

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🧠 When to Use Variable Swapping

Use Case	Description
Sorting algorithms	Like Bubble Sort or Selection Sort
Array manipulation	Rearranging key-value pairs
Data structure logic	Stack or queue element shifting
Game mechanics	Player turns, position updates, etc.
Math computations	Rotating values or adjusting coordinates

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🧪 Example – Swapping Elements in an Array

$arr = [1, 2, 3, 4];

// Swap index 0 and 2
[$arr[0], $arr[2]] = [$arr[2], $arr[0]];

print_r($arr); // Output: [3, 2, 1, 4]

📌 Useful for in-place algorithms or dynamic array updates

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🛡️ Tips & Best Practices

• ✅ Use destructuring ([$a, $b] = [$b, $a]) when readability matters
• ✅ Stick with a temp variable for PHP 5.x compatibility
• ❌ Avoid swapping without a plan — can make logic harder to debug if overused
• ✅ Comment your swaps when used inside loops or complex structures

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📌 Summary – Recap & Next Steps

Swapping variables is a core programming concept with multiple ways to achieve in PHP. Whether you prefer traditional temp variables or modern array destructuring, PHP gives you the flexibility to write clean and performant code.

🔍 Key Takeaways:

• Use a temp variable for broad PHP compatibility
• Use list destructuring for concise and modern PHP 7+ code
• Swapping is essential in algorithms, games, and data transformations
• Use clearly labeled variables for maintainability

⚙️ Real-World Use Cases:
Sorting arrays, turn-based game logic, array reordering, in-place data updates, matrix transformations

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❓ Frequently Asked Questions (FAQs)

❓ Can I swap three or more variables at once in PHP?
✅ Yes. Use destructuring like [$a, $b, $c] = [$b, $c, $a];

❓ Is swapping with arithmetic operations recommended?
❌ No. Avoid $a = $a + $b; $b = $a - $b; as it can cause overflow or type issues.

❓ What PHP version supports destructuring for swapping?
✅ PHP 7.1 or higher supports list destructuring for swapping variables.

❓ Can I swap array elements in a loop?
✅ Yes. Use [$arr[$i], $arr[$j]] = [$arr[$j], $arr[$i]]; inside a loop.

❓ Is there a built-in PHP function for swapping variables?
❌ No built-in function exists — manual swapping is required.

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