Creating a reference to variable directly from string (without switch statement)

Question

I know the title is not very clear so here it's in code:

function output($selector){
    $one = 1;
    $two = 2;
    $there = 3;

    return ? //should return 1 without if or switch statement
}


echo output('one');

If this is possible, how?

BoltClock · Accepted Answer · 2011-05-21 23:17:31Z

1

Use a variable variable by prefixing the $selector variable with another $:

return $$selector;

Remember to do sanity checks and/or implement default values, so you don't end up generating unnecessary undefined variable errors and such from within your function.

answered May 21, 2011 at 23:17

BoltClock

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2 Comments

Chad Over a year ago

I was just going to try that but my code editor (notepad++) led me to believe that it would not be right. :)

BoltClock Over a year ago

@Chad: I know what you mean, but don't worry, it's just a bug with Notepad++'s syntax highlighting.

Zecc · Accepted Answer · 2011-05-21 23:33:00Z

1

I personally don't like the idea of using variable variables.

Why not just use an array?

function output($selector){
    $choices = array(
        'one' => 1,
        'two' => 2,
        'there' => 3,
    );

    return $choices[$selector];
}

or if your values aren't set in stone:

function output($selector){
    // Complex calculations here
    $one = 1;
    $two = 2;
    $there = 3;

    return array(
        'one' => $one,
        'two' => $two,
        'there' => $there,
    )[$selector];
}

(Yes, I realize this is pretty similar to using a switch statement)

answered May 21, 2011 at 23:33

Zecc

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Comments

user680786 · Accepted Answer · 2011-05-21 23:20:02Z

0

function output($selector){
    $one = 1;
    $two = 2;
    $there = 3;

    return $$selector;
}


echo output('one');

But it's not most clever thing.

answered May 21, 2011 at 23:20

user680786

2 Comments

Chad Over a year ago

"not most clever thing" can you explain why please?

user680786 Over a year ago

BoltClock answered more detailed. In addition: IDE will not be able to suggest code completion in this case - typos, errors. Or in variable can be some kind of users input and it will be security issue.

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