How to get object property from each object in an array?

Assuming I have an array of objects in PHP, something like:

Array (
    [0] => stdClass Object (
            [id] => 1
            [name] => Title One
        )    
    [1] => stdClass Object (
            [id] => 2
            [name] => Title Two
        )

    [2] => stdClass Object (
            [id] => 7
            [name] => Title Seven
        )
)

What is the best way (i.e. fastest) to get an array of the IDs? i.e. array(1,2,7) I can loop manually but I feel there must be a better method.

Just saw this in the similar questions but there's a little debate over whether the accepted answer is rea开发者_如何学运维lly the best way, plus it's from 2 years ago. I'm on PHP 5.3.

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You can use array_map to get the IDs from each element.

function getID($a){
   return $a->id;
}
$IDs = array_map('getID', $array);

Demo: http://ideone.com/nf3ug

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Since PHP 7.0 you may use the builtin function array_column for that, which takes an input array and the name of the property you want to pluck:

$ids = array_column($input, 'id');
// array(0 => 1, 1 => 2, 2 => 7)

As a third parameter, you may optionally supply an index-key as well:

$ids = array_column($input, 'name', 'id');
// array(1 => 'Title One', 2 => 'Title Two', 7 => 'Title Seven')

Please note that, although it's already available in PHP 5.5.0, support for an array of objects was first introduced in PHP 7.0.

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The fastest way is simply looping (foreach, for, while). Using callback functions will incur unnecessary overhead.

I would look to see if there's a way to create the list via the code that is building the initial array of objects.

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I'm using RedBean and for some reason passing in "getID" didn't work for me, so here is how I done it:

$ids = array_map(function($val){return $val->id;}, $objects);

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You can do it easily with ouzo goodies

$result = array_map(Functions::extract()->id, $objects);

or with Arrays (from ouzo goodies)

$result = Arrays::map($objects, Functions::extract()->id);

Check out: http://ouzo.readthedocs.org/en/latest/utils/functions.html#extract

See also functional programming with ouzo (I cannot post a link).

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Did you try the array_keys function?

EDIT:

<?php 
   $ids = array();
   for($c=0; $c<count($the_array); $c++) $ids[$c] = $the_array[$c]->id;
?>

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You can also use extract_property() which is a well tested library designed specifically for this job (disclaimer: I am the author).