Summary: in this tutorial, you will learn about the most commonly used PHP assignment operators.
Introduction to the PHP assignment operator
PHP uses the =
to represent the assignment operator. The following shows the syntax of the assignment operator:
$variable_name = expression;
Code language: PHP (php)
On the left side of the assignment operator (=
) is a variable to which you want to assign a value. And on the right side of the assignment operator (=
) is a value or an expression.
When evaluating the assignment operator (=
), PHP evaluates the expression on the right side first and assigns the result to the variable on the left side. For example:
$x = 10;
$y = 20;
$total = $x + $y;
Code language: PHP (php)
In this example, we assigned 10 to $x, 20 to $y, and the sum of $x and $y to $total.
The assignment expression returns a value assigned, which is the result of the expression in this case:
$variable_name = expression;
Code language: PHP (php)
It means that you can use multiple assignment operators in a single statement like this:
$x = $y = 20;
Code language: PHP (php)
In this case, PHP evaluates the right-most expression first:
$y = 20
Code language: PHP (php)
The variable $y
is 20
.
The assignment expression $y = 20
returns 20
so PHP assigns 20
to $x
. After the assignments, both $x
and $y
equal 20.
Arithmetic assignment operators
Sometimes, you want to increase a variable by a specific value. For example:
$counter = 1;
$counter = $counter + 1;
Code language: PHP (php)
How it works.
- First,
$counter
is set to1
. - Then, increase the
$counter
by1
and assign the result to the$counter
.
After the assignments, the value of $counter
is 2
.
PHP provides the arithmetic assignment operator +=
that can do the same but with a shorter code. For example:
$counter = 1;
$counter += 1;
Code language: PHP (php)
The expression $counter += 1
is equivalent to the expression $counter = $counter + 1
.
Besides the +=
operator, PHP provides other arithmetic assignment operators. The following table illustrates all the arithmetic assignment operators:
Operator | Example | Equivalent | Operation |
---|---|---|---|
+= | $x += $y | $x = $x + $y | Addition |
-= | $x -= $y | $x = $x – $y | Subtraction |
*= | $x *= $y | $x = $x * $y | Multiplication |
/= | $x /= $y | $x = $x / $y | Division |
%= | $x %= $y | $x = $x % $y | Modulus |
**= | $z **= $y | $x = $x ** $y | Exponentiation |
Concatenation assignment operator
PHP uses the concatenation operator (.) to concatenate two strings. For example:
<?php
$greeting = 'Hello ';
$name = 'John';
$greeting = $greeting . $name;
echo $greeting;
Code language: HTML, XML (xml)
Output:
Hello John
By using the concatenation assignment operator you can concatenate two strings and assigns the result string to a variable. For example:
<?php
$greeting = 'Hello ';
$name = 'John';
$greeting .= $name;
echo $greeting;
Code language: HTML, XML (xml)
Summary
- Use PHP assignment operator (
=
) to assign a value to a variable. The assignment expression returns the value assigned. - Use arithmetic assignment operators to carry arithmetic operations and assign at the same time.
- Use concatenation assignment operator (
.=
)to concatenate strings and assign the result to a variable in a single statement.