Basic PHP question the use of $$

This is a basic PHP question.I am Java/C++ guy trying to understand a third party code and I am stuck at how things work in PHP

 if($person == 'male' ){
            $user = $$person;
            $name = '<b>'.ucwords($user->username).";
            return $name;
           
         
        }
I am wondering how $person which has a string can contain in  if($person == 'male' )
the comeplete user object in $$person.

Is it dereferencing (cant be) does $$ have a special meaning ..any example or online tutorial will be of a great help.

Thanks
   
micro_learnerAsked:
Who is Participating?
I wear a lot of hats...

"The solutions and answers provided on Experts Exchange have been extremely helpful to me over the last few years. I wear a lot of hats - Developer, Database Administrator, Help Desk, etc., so I know a lot of things but not a lot about one thing. Experts Exchange gives me answers from people who do know a lot about one thing, in a easy to use platform." -Todd S.

mltsyCommented:
This example doesn't make a lot of sense to me, but this is how $$ works:
http://us3.php.net/manual/en/language.variables.variable.php

Basically it first replaces $person with 'male' and then evaluates what remains: $male
0

Experts Exchange Solution brought to you by

Your issues matter to us.

Facing a tech roadblock? Get the help and guidance you need from experienced professionals who care. Ask your question anytime, anywhere, with no hassle.

Start your 7-day free trial
Hube02Commented:
As mltsy says, the example you give makes very little sense at all.

in this case you could simplify the statement in several ways.

first:

if($person == 'male' ){
  $user = $male;
  $name = '<b>'.ucwords($user->username).";
  return $name;
}

then:

if($person == 'male' ){
  $name = '<b>'.ucwords($male->username).";
  return $name;
}

then:

if($person == 'male' ){
  return = '<b>'.ucwords($male->username).";
}

.... there seems to be no reason to use the $$ in this case other than to make the code obtuse and harder to understand
0
ddrudikCommented:
Since at soon as indexes are involved in the varname the concern is for ambiguity unless you use { }, possibly using { } is a good habit since code within { } is evaluated first.  Also I removed ." from the example since the double-quote seemed to be unmatched (maybe the example was trunacted before posting the question).
 if($person == 'male' ){
            $user = ${$person};
            $name = '<b>'.ucwords($user->username);
            return $name;
        }
 
or:
 
 if($person == 'male' ){
            return '<b>'.ucwords(${$person}->username);
        }

Open in new window

0
Hube02Commented:
$$ is usually used when you will not know the exact value of something, which is why its use in the example you posted does not make sense.

switch ($person) {
  case 'male':
  case 'female':
    return '<b>'.ucwords(${$person}->username);
    break;
  default:
    // person has no gender
    // call routine to get the user's gender
}

in the above situation, while we know that $person can be either 'male' or 'female' when we use it in the return we don't know which one we will be returning. In this case it makes sense to use the $$ construct.

And ddrudik is correct, you should always use the curly brackets to make the code clearer. using ${$person} serves two purposes. First, it is more clear what we are doing, that is, using the value of a variable as a variable name. Second, we know by looking at it that this is not a typo and that the person that did the coding actually meant to use $$person and not $person.
0
It's more than this solution.Get answers and train to solve all your tech problems - anytime, anywhere.Try it for free Edge Out The Competitionfor your dream job with proven skills and certifications.Get started today Stand Outas the employee with proven skills.Start learning today for free Move Your Career Forwardwith certification training in the latest technologies.Start your trial today
PHP

From novice to tech pro — start learning today.

Question has a verified solution.

Are you are experiencing a similar issue? Get a personalized answer when you ask a related question.

Have a better answer? Share it in a comment.