What is the difference between $b and $$b?

Question

I have doubt regrading '$' usage in PHP. In php is their any difference between between $b and $$b? What will be the output then for $b and $$b?

Read here http://php.net/manual/en/language.variables.variable.php — Shankar Narayana Damodaran, Dec 10 '13 at 06:34
This is a fairly valid question, but had you typed it in to Google, you would have gotten your answer without going through the hassle of being massively downvoted on SO :| — brandonscript, Dec 10 '13 at 07:04
First i am sorry that i answered my own question.Because i got an answer from google itself. As i wanted to share what i got, i answered and shared with people. People come here to get a complex solution explained in a simple way.Google has everything in it i agree.. If all looks in google then why we would use stackoverflow? — user3085576, Dec 11 '13 at 04:13

user3085576 · Accepted Answer · 2013-12-11T06:22:25.307

The only difference between $message and $$b is that, $b is a normal variable and $$bis variable to variable. The difference in functioning is shown below:

When declaring a variable in PHP the variable gets declared like this

$b//which is simply a variable

To store the data to assign the value to it we write like

$b= “ride”; //assigned the string to the variable

echo $b; // it will print the value

Whereas if you want to display the variable to variable then you use

$var="Hello";

$b="var";

echo $b; //print var

echo $$b; //print Hello.

score 1 · Answer 2 · answered Dec 10 '13 at 06:37

From the PHP manual:

A normal variable is set with a statement such as:

$a = 'hello';

A variable variable takes the value of a variable and treats that as the name of a variable. In the above example, hello, can be used as the name of a variable by using two dollar signs. i.e.

$$a = 'world';

At this point two variables have been defined and stored in the PHP symbol tree: $a with contents "hello" and $hello with contents "world".

What is the difference between $b and $$b?

2 Answers2