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PHP while Loop Statement

Description

Suppose you want to calculate gross salaries of 20 different persons or take a list of maximum and minimum temperatures of a certain month or a year, the while loop is ideal to solve these types of cases.

The while statement is simple, it executes the statement(s) repeatedly as long as the condition is true. The condition is checked every time at the beginning of the loop.

Syntax:

while ( condition is true )
execute this statement ;
The general form of while statement :
        initialize loop counter;
while (test loop counter using condition)
{
execute the statement
....... 
.......
.......
increment loop counter
}

Example :

The following example print "Increment Number" with $x1 value as well as "Hello world" five times. 

<?php
$x1=1;
while ($x1<=5)
{
echo "Increment Number : $x1 <br />";>
echo "Hello World <br />";
$x1=$x1+1;
}
?>

Output :

Increment Number : 1 
Hello World 
Increment Number : 2 
Hello World 
Increment Number : 3 
Hello World 
Increment Number : 4 
Hello World
Increment Number : 5 
Hello World

View the example in the browser

Pictorial representation of while loop

php-while-loop

See also

do while, for statement

Previous: if else elseif statement
Next: do-while statement



PHP: Tips of the Day

How to Sort Multi-dimensional Array by Value?

Try a usort, If you are still on PHP 5.2 or earlier, you'll have to define a sorting function first:

Example:

function sortByOrder($a, $b) {
    return $a['order'] - $b['order'];
}

usort($myArray, 'sortByOrder');

Starting in PHP 5.3, you can use an anonymous function:

usort($myArray, function($a, $b) {
    return $a['order'] - $b['order'];
});

And finally with PHP 7 you can use the spaceship operator:

usort($myArray, function($a, $b) {
    return $a['order'] <=> $b['order'];
});

To extend this to multi-dimensional sorting, reference the second/third sorting elements if the first is zero - best explained below. You can also use this for sorting on sub-elements.

usort($myArray, function($a, $b) {
    $retval = $a['order'] <=> $b['order'];
    if ($retval == 0) {
        $retval = $a['suborder'] <=> $b['suborder'];
        if ($retval == 0) {
            $retval = $a['details']['subsuborder'] <=> $b['details']['subsuborder'];
        }
    }
    return $retval;
});

If you need to retain key associations, use uasort() - see comparison of array sorting functions in the manual

Ref : https://bit.ly/3i77vCC