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.
To understand the difference better, let's see some examples.
Example 1
$$x = 200;
echo $x."
";
echo $$x."
";
echo $abc;
?>
Output:
In the above example, we have assigned a value to the variable x as abc. Value of reference variable $$x is assigned as 200.
Now we have printed the values $x, $$x and $abc.
Example2
$$x="Lucknow";
echo $x. "
";
echo $$x. "
";
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.
Now we have printed the values $x, $$x and a string.
Example3
${$name}="Dog";
${${$name}}="Monkey";
echo $name. "
";
echo ${$name}. "
";
echo $Cat. "
";
echo ${${$name}}. "
";
echo $Dog. "
";
?>
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.
Now we have printed the values as $name, ${$name}, $Cat, ${${$name}} and $Dog.
