PHP Loops for, foreach, while, do while: Tutorial, Examples, FAQs & Interview Tips

Loops execute a block of code repeatedly as long as a condition is true. PHP provides four loop types: while, do-while, for, and foreach.

while and do-while Loops

A while loop checks the condition before each iteration. A do-while loop always executes at least once because the condition is checked after the body.

while / do-while

<?php
// while loop
$i = 1;
while ($i <= 5) {
    echo "Count: $i\n";
    $i++;
}

// do-while loop - runs at least once
$n = 10;
do {
    echo "n = $n\n";
    $n++;
} while ($n < 5);
// Output: n = 10  (runs once even though 10 < 5 is false)
?>

for Loop

The for loop is ideal when you know the exact number of iterations. It combines initialization, condition, and increment in one line.

for Loop

<?php
// Basic for loop
for ($i = 0; $i < 5; $i++) {
    echo "Item $i\n";
}

// Countdown
for ($i = 5; $i >= 1; $i--) {
    echo "$i ";
}
// Output: 5 4 3 2 1

// Nested loops - multiplication tl-table
for ($row = 1; $row <= 3; $row++) {
    for ($col = 1; $col <= 3; $col++) {
        echo $row * $col . "\t";
    }
    echo "\n";
}
?>

foreach Loop

The foreach loop is designed for iterating over arrays. Use the key => value syntax to access both keys and values.

foreach Loop

<?php
// Indexed array
$colors = ["red", "green", "blue"];
foreach ($colors as $color) {
    echo $color . "\n";
}

// Associative array with key => value
$person = ["name" => "Alice", "age" => 30, "city" => "NYC"];
foreach ($person as $key => $value) {
    echo "$key: $value\n";
}

// break and continue
for ($i = 0; $i < 10; $i++) {
    if ($i === 5) break;    // stop loop at 5
    if ($i % 2 === 0) continue; // skip even numbers
    echo $i . " ";
}
// Output: 1 3
?>

Key Takeaways

PHP supports for, while, do-while, foreach, and the alternative syntax (for(): ... endfor;).
foreach is the most convenient loop for arrays - it iterates over values or key-value pairs.
Use break to exit a loop and continue to skip to the next iteration.
break 2 exits two nested loops at once - useful for breaking out of nested structures.
The list() function (or [] destructuring) can unpack array values in foreach loops.
Avoid modifying an array while iterating over it with foreach - use a copy or index-based loop instead.

PHP Loops for, foreach, while, do while: Tutorial, Examples, FAQs & Interview Tips

while and do-while Loops

for Loop

foreach Loop

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