What's the difference between $,$,$$?

Question

I have doubt using dollar symbol in program

Answer 1

$ => Variable
$ => Variable by Name
$$ => Variable by Name x2

Take these examples:

1.
$x = 5;
echo $x; 《5》

2.
$dog = 5;
$x = "dog";
echo $x; 《5》

$x controls the value of "x" and returns the variable with that name, in this case... dog variable's value!

3.
$dog = 5;
$cat = "dog";
$x = "cat";
echo $$x; 《5》

$$x controls the value of "x" and returns the variable with that name, then.. $cat, this last contains the value "dog" and since we putted three dollar signs, it will returns the dog variable's value!

Answer 2

Thank you maz

Answer 3

22.05.17