The $x (single dollar) is the normal variable with the name x that stores any value like string, integer, float, etc. The $$x (double dollar) is a reference variable that stores the value which can be accessed by using $ symbol before $x value.
From the given figure below, it can be easily understood that:
- $x stores the value “Geeks” of String type.
- Now reference variable $$x stores the value “for Geeks” in it of String type.
So, the value of “for geeks” can be accessed by two ways which are listed below:
- By using Reference variable directly. Example: echo $$x;
- By using the value stored at variable $x as a variable name for accessing the “for Geeks” value. Example: echo $Geeks; which will give output as “for Geeks” (without quote marks).
Input : $x = "Geeks"; $$x = for Geeks; echo "$x "; echo "$$x;"; echo $Geeks; Output : Geeks for Geeks for Geeks Input : $x = "Rajnish"; $$x = "Noida"; echo "$x lives in " . $Rajnish; Output : Rajnish lives in Noida
Below examples illustrate the use of $ and $$ in PHP:
Geeks GeeksforGeeks GeeksforGeeks
Geeks GeeksforGeeks computer science computer science