PHP | $ vs $$ operator - ❤️️ Online PHP tutorial

The $ operator in PHP is used to declare a variable. In PHP, a variable starts with the $ sign followed by the name of the variable. For example, below is a string variable:

$var_name = "Hello World!";

The $var_name is a normal variable used to store a value. It can store any value like integer, float, char, string etc. On the other hand, the $$var_name is known as reference variable where $var_name is a normal variable. The $$var_name used to refer to the variable with the name as value of the variable $var_name.

Examples:

Input :  $Hello = "Beginner for Beginner"
         $var = "Hello"
         echo $var
         echo $$var
Output : Hello
         Beginner for Beginner

Input :  $GFG = "Welcome to w3wiki"
         $var = "GFG"
         echo $var
         echo $$var
Output : GFG
         Welcome to w3wiki

Explanation: In the above example, $var stores the value “Hello”, so $$var will refer to the variable with name Hello i.e., $Hello.

Below program will illustrate the $ and $$ operator in PHP.

<?php 
  
// Variable declaration and initialization  
$var = "Hello"; 
$Hello = "w3wiki"; 
  
// Display the value of $var and $$var 
echo $var . "\n"; 
echo $$var; 
  
echo "\n\n"; 
  
// Variable declaration and initialization  
$var = "GFG"; 
$GFG = "Welcome to w3wiki"; 
  
// Display the value of $var and $$var 
echo $var. "\n"; 
echo $$var; 
?> 

Output:

Hello
w3wiki

GFG
Welcome to w3wiki

PHP | $ vs $$ operator

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