php computing a variable on the fly using anonymous functions

Question

Sometimes while initializing variables, you want to pass them values that are too complex to be computed in a single command, so you usually either compute a dummy variable before and then pass its value, or define a function elsewhere, and pass it's return value to our variable.

My question (wish) is, is it possible instead compute to a variable on the fly using anonymous functions?

for example, instead of use this:

$post = get_post();
$id = $post->ID;

$array = array(
    'foo' => 'hi!',
    'bar' => $id
);

Lets use something like this:

$array = array(
    'foo' => 'hi!',
    'bar' => (function(){
        $post = get_post();
        return $post->ID;
    })
);

Code is totaly random.

"Code is totaly random." a very unlikely combination of letters to come from any kind of random generation — user557846
– user557846, Commented Sep 5, 2012 at 0:06
@PeeHaa yes, it returns Closure::__set_state(array( )) since closures are instances of the Closure class. — Bakaburg
– Bakaburg, Commented Sep 5, 2012 at 0:21

Community · Accepted Answer · 2017-05-23 12:04:47Z

1

In your example, the following would do just fine:

$array = array('foo'=>'hi!','bar'=>(get_post()->ID));

However, with consideration to your question being a bit more open ended and not specific to your code snippet, you may find this stackoverflow answer acceptable.

$a = array('foo' => call_user_func(
    function(){
        $b = 5;
        return $b;
    })
);
var_dump($a);

edited May 23, 2017 at 12:04

CommunityBot

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answered Sep 5, 2012 at 0:13

zamnuts

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3 Comments

Bakaburg Over a year ago

one side question: why you put $ before ID into (get_post()->$ID)? and the parenthesis are needed?

zamnuts Over a year ago

@Bakaburg my bad on the $ before the ID, i have updated the post with proper syntax. also the parens are most likely not needed, i just didn't test my code and was playing it safe :)

zamnuts Over a year ago

please consider memory leaks when using this type of notation: stackoverflow.com/a/6657911/1481489 (although it has been fixed in 5.3.10) and also general memory overhead and speed: dboskovic.typepad.com/david-boskovic/2010/04/…

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