Web Technologies

PHP Loops

Are you wondering why I am writing this very basic article of type of PHP loops? Just because sometime we get confused which loop we need to use in program based on the situation.

There are 4 type of loop in PHP

  1. For Loop – When we know the number of iterations
  2. While Loop – When we don’t know number of iterations
  3. Do..While Loop – When we don’t know number of iterations and we want to perform some actions for each loop process. For example. Generating a random number each time till we got 6. This is the case in dice rolling example.
  4. Foreach Loop – This is loop for arrays.

If the condition in a while loop is false, then not a single statement inside the Loop will be executed, whereas in a do-while Loop, if the condition is false, then the body of the Loop is executed at least once.

Here is the simple example to demonstrate loops.

<?php

echo 'Hello world';
// There are 4 types of loop
// for
// while
// do..while
// foreach
echo '<br>';

// For loop is used when the number of iterations is already known.

for ($i = 1; $i < 20; $i++) {
    # code...
    echo $i . '</br>';
}
echo '</br>';

// While loop is used when the number of iterations is already Unknown
$a = 1;
while ($a <= 5) {
    # code...
    echo $a . '</br>';
    $a++;
}
echo '</br>';


// perform this action in loop untill condition fulfilled.
do {
    # code...
    $b = rand(1, 6);
    echo $b . '</br>';
} while ($b != 6);

// loops through a block of code for each element in an array
echo '<br>';
$ary = [2, 4, 6, 8, 10, 12, 14, 16, 18, 20];

foreach ($ary as $key => $value) {
    # code...
    echo $key . ' - ' . $value;
    echo '<br>';
}