PHP $ and $$

 PHP $ and $$ Variables

The $var (single dollar) is a normal variable with the name var that stores any value like string, integer, float, etc.

The $$var (double dollar) is a reference variable that stores the value of the $variable inside it.

Example1:

<?php  

$x = "abc";  

$$x = 200;  

echo $x."<br/>";  

echo $$x."<br/>";  

echo $abc;  

?>  

Output:

abc

200

200

In the above example, we have assigned a value to the variable x as abc. Value of reference variable $$x is assigned as 200.

Example2

<?php  

 $x="U.P";  

$$x="Lucknow";  

echo $x. "<br>";  

echo $$x. "<br>";  

echo "Capital of $x is " . $$x;  

?>  

Output:

In the above example, we have assigned a value to the variable x as U.P. Value of reference variable $$x is assigned as Lucknow.

Example3

<?php  

$name="Cat";  

${$name}="Dog";  

${${$name}}="Monkey";  

echo $name. "<br>";  

echo ${$name}. "<br>";  

echo $Cat. "<br>";  

echo ${${$name}}. "<br>";  

echo $Dog. "<br>";  

?>  

Output:

In the above example, we have assigned a value to the variable name Cat. Value of reference variable ${$name} is assigned as Dog and ${${$name}} as Monkey.