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PHP Assignment Operators

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

Variables can be incremented or decremented by 1 with ++ or --, respectively. They can either precede or succeed variables and slightly vary semantically, as shown below.

Example:

$i = 1;
echo $i; // Prints 1
// Pre-increment operator increments $i by one, then returns $i
echo ++$i; // Prints 2
// Pre-decrement operator decrements $i by one, then returns $i
echo --$i; // Prints 1
// Post-increment operator returns $i, then increments $i by one
echo $i++; // Prints 1 (but $i value is now 2)
// Post-decrement operator returns $i, then decrements $i by one
echo $i--; // Prints 2 (but $i value is now 1)

More information about incrementing and decrementing operators can be found in the official documentation.