🔁 PHP Loop Types – for, foreach, while, do…while Explained

A complete guide to while, do...while, for, and foreach loops in PHP with examples, syntax, and best practices.

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🧲 Introduction – Why Loops Matter in PHP

Loops are essential for executing a block of code multiple times. Whether you’re displaying a list of records, generating repetitive HTML, or calculating values — PHP’s loop structures help automate repetitive tasks efficiently.

🎯 In this guide, you’ll learn:

• The 4 primary loop types in PHP
• Syntax and use cases for each loop
• How to control loop execution with break and continue
• Loop performance tips and clean coding practices

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🔄 1. while Loop

Repeats as long as the condition is true.

$i = 1;

while ($i <= 3) {
    echo "Count: $i <br>";
    $i++;
}

🔍 Output:

Count: 1
Count: 2
Count: 3

📘 Use Case: Unknown number of iterations; condition-based execution.

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🔁 2. do...while Loop

Executes the block at least once, even if the condition is false.

$j = 1;

do {
    echo "Step: $j <br>";
    $j++;
} while ($j <= 3);

🔍 Output:

Step: 1
Step: 2
Step: 3

📘 Use Case: When at least one execution is guaranteed, like input validation.

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🔃 3. for Loop

Best for a known number of iterations.

for ($k = 0; $k < 3; $k++) {
    echo "Loop: $k <br>";
}

🔍 Output:

Loop: 0
Loop: 1
Loop: 2

📘 Use Case: Fixed iteration counts, numeric counters, indexed arrays.

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🔄 4. foreach Loop

Specifically designed to iterate over arrays and objects.

$colors = ['red', 'green', 'blue'];

foreach ($colors as $color) {
    echo "Color: $color <br>";
}

🔍 Output:

Color: red
Color: green
Color: blue

📘 Use Case: Array iteration. Cleanest loop for key/value pairs.

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🧭 foreach with Keys

$person = ['name' => 'John', 'age' => 30];

foreach ($person as $key => $value) {
    echo "$key: $value <br>";
}

🔍 Output:

name: John
age: 30

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⛓️ Loop Control: break and continue

🚫 break – Exit the loop entirely

for ($x = 1; $x <= 5; $x++) {
    if ($x == 3) break;
    echo $x . " ";
}

🔍 Output: 1 2

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🔂 continue – Skip current iteration

for ($x = 1; $x <= 5; $x++) {
    if ($x == 3) continue;
    echo $x . " ";
}

🔍 Output: 1 2 4 5

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🔬 Loop Selection Summary

Loop Type	When to Use
while	Loop until condition is false
do...while	Always run at least once
for	Known number of steps
foreach	Best for arrays and collections

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🧠 Best Practices

• ✅ Use foreach for arrays — it’s faster and cleaner
• ✅ Initialize variables outside the loop
• ✅ Use break for exiting early
• ✅ Minimize logic inside loops for performance
• ❌ Avoid modifying the array you’re looping over (foreach may behave unpredictably)

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📌 Summary – Recap & Next Steps

Loops help automate repetitive tasks in your PHP scripts, from listing users to validating forms. Mastering each loop type makes your code more efficient and clean.

🔍 Key Takeaways:

• while — Runs while condition is true
• do...while — Runs at least once
• for — Best for numeric or counted loops
• foreach — Ideal for arrays and objects

⚙️ Real-World Use Cases:
Used in shopping carts, pagination, report generation, and dynamic UI rendering.

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❓ Frequently Asked Questions (FAQs)

❓ Which loop is best for arrays in PHP?
✅ foreach — It’s designed for array traversal and avoids indexing errors.

❓ When should I use do...while?
✅ When the loop must run at least once, like reading user input.

❓ Can I use break inside foreach?
✅ Yes — break exits any type of loop.

❓ What’s the difference between continue and break?
✅ continue skips current iteration; break exits the loop entirely.

❓ Is foreach faster than for?
✅ Generally yes, especially for associative arrays.

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