What is $$ in php?

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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!

Some of us can understand that it would be difficult to know how to search for $$. — DOK, Jan 21 '12 at 19:22

score 6 · Answer 1 · answered Jan 21 '12 at 19:21

6

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

answered Jan 21 '12 at 19:21

Treffynnon

score 1 · Answer 2 · answered Jan 21 '12 at 19:20

1

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

answered Jan 21 '12 at 19:20

Darin Dimitrov

score 1 · Answer 3 · answered Jan 21 '12 at 19:21

1

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

answered Jan 21 '12 at 19:21

Yaron U.

score 0 · Answer 4 · answered Jan 21 '12 at 19:23

0

running this code would set $name

$value="name";
$$value="testing";

in other words, $name is now equal to "testing"

answered Jan 21 '12 at 19:23

Adam F

4 Answers4