3 replies to this topic

[murugavelb]

One of my senior ask me that, what is the difference between $ and $$ (in php)?
Can u guys help me ?

[wim DC]

Agree, googling for "$" doesn't give you much, so here are the actual names:

$ = php variable
$$ = php variable variable(Ye seriously)

google it.

[murugavelb]

I got the answer with little confusion....
Actually here we use a value(Christine_Nothdurfter) of variable as a variable name($Christine_Nothdurfter).... But what is the use of it ?

Actual code:

<?php
error_reporting(E_ALL);

$name = "Christine_Nothdurfter";
// not Christine Nothdurfter
// you are not allowed to leave a space inside a variable name ;)
$$name = "'s students of Tyrolean language ";

print " $name{$$name}<br>";
print "$name$Christine_Nothdurfter";
// same
?>



Output :

Christine_Nothdurfter's students of Tyrolean language
Christine_Nothdurfter's students of Tyrolean language

[Orjan]

You can have variable variables. For example, if you in object oriented programming don't know what class you need to instanciate, you can do

$class = "myclass";

$object = new $class();

Now $object is a object of type myclass, which could be changed to whatever from for example a database query teling which class to use.