PHP Assignment Operators

Last update on May 28 2022 12:34:41 (UTC/GMT +8 hours)

Description

Assignment operators allow writing a value to a variable. The first operand must be a variable and the basic assignment operator is "=". The value of an assignment expression is the final value assigned to the variable. In addition to the regular assignment operator "=", several other assignment operators are composites of an operator followed by an equal sign.

Interestingly all five arithmetic operators have corresponding assignment operators, Here is the list.

The following table discussed more details of the said assignment operators.

Shorthand	Expression	Description
$a+= $b	$a = $a + $b	Adds 2 numbers and assigns the result to the first.
$a-= $b	$a = $a -$b	Subtracts 2 numbers and assigns the result to the first.
$a*= $b	$a = $a*$b	Multiplies 2 numbers and assigns the result to the first.
$a/= $b	$a = $a/$b	Divides 2 numbers and assigns the result to the first.
$a%= $b	$a = $a%$b	Computes the modulus of 2 numbers and assigns the result to the first.

Example:

<?php
$x1=100;
$x2=200;
$x3=300;
$x4=400;
$x5=500;
$x1+= 100;
echo " $x1 <br />";
$x2-= 200;
echo " $x2 <br />";
$x3*= 300;
echo " $x3 <br />";
$x4/= 400;
echo " $x4 <br />";
$x5%= 500;
echo " $x5 <br />";
$x=($y=11)+9;
echo " Value of x & y is :  $x  $y <br />";
?>

Output:

200
0
90000
1
0
Value of x & y is : 20 11

View the example in the browser

Previous: Logical Operators
Next: Bitwise Operators

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