What is $$ in php?

2018-06-21 00:58:38

Possible Duplicate:
What does $$ mean in PHP?
Double dollar sign php

What is $$ in php. This question is asked in a recent interview for a web developer position. Thanks in advance!

This is a variable variable. They work by using a variable to contain the name of another variable like so:

$var = 'test';
$test = 'echod variable';
echo $$var;
// output echod variable

It's a variable variable:

Sometimes it is convenient to be able to have variable variable names. That is, a variable name which can be set and used dynamically.

dynamic variable name,

for example

for($i = 0; $i<10; $i++)
{
  $var_name = "d".$i;
  echo $$var_name;
}

will echo the variables $d0, $d1, $d2, $d3... $d9

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