loops Overview

Overview of PHP Loops

Loops in PHP are used to execute a block of code repeatedly as long as a specified condition is true. They are essential for tasks that require repetition, such as iterating over arrays, generating sequences, or processing data.

1. while Loop

The while loop executes a block of code as long as the condition is true.

while (condition) {
    // Code to be executed
}

Example:

<?php
$i = 1;
while ($i <= 5) {
    echo $i . "<br>";
    $i++;
}
?>

Output

2. do...while Loop

This loop is similar to while, but it ensures that the code block runs at least once, even if the condition is false at the start.

do {
    // Code to be executed
} while (condition);

Example:

<?php
$i = 1;
do {
    echo $i . "<br>";
    $i++;
} while ($i <= 5);
?>

Output

3. for Loop

The for loop is used when the number of iterations is known. It has three parts: initialization, condition, and increment/decrement.

for (initialization; condition; increment) {
    // Code to be executed
}

Example:

<?php
for ($i = 1; $i <= 5; $i++) {
    echo $i . "<br>";
}
?>

Output

4. foreach Loop

The foreach loop is specifically used to iterate over arrays.

foreach ($array as $value) {
    // Code to be executed
}

With key-value pairs:

foreach ($array as $key => $value) {
    // Code using $key and $value
}

Example:

<?php
$colors = ["red", "green", "blue"];
foreach ($colors as $color) {
    echo $color . "<br>";
}
?>

Output

Associative Array Example:

<?php
$user = ["name" => "John", "age" => 25];
foreach ($user as $key => $value) {
    echo "$key: $value<br>";
}
?>

Output

5. Loop Control Statements

break: Exits the loop immediately.

continue: Skips the current iteration and continues with the next one.

Example with break:

<?php
for ($i = 1; $i <= 10; $i++) {
    if ($i == 6) break;
    echo $i . "<br>";
}
?>

Output

Example with continue:

<?php
for ($i = 1; $i <= 5; $i++) {
    if ($i == 3) continue;
    echo $i . "<br>";
}
?>

Output

Summary Table

Conclusion

PHP loops are powerful tools for repeating code efficiently. Choosing the right loop depends on your specific use case—whether you're iterating through a numeric range, an array, or performing a task until a condition is met.

Understanding these loop structures is fundamental to writing efficient PHP applications that can handle repetitive tasks with ease.