168

Let's assume I have the following multidimensional array (retrieved from MySQL or a service): 

array(
    array(
        [id] => xxx,
        [name] => blah
    ),
    array(
        [id] => yyy,
        [name] => blahblah
    ),
    array(
        [id] => zzz,
        [name] => blahblahblah
    ),
)

Can we get an array of ids in one "built-in" php function call? or one line of code?
I am aware of the traditional looping and getting the value but I don't need this: 

foreach($users as $user) {
    $ids[] = $user['id'];
}
print_r($ids);

Maybe some array_map() and call_user_func_array() can do the magic.

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4
  • "Can we get an array of ids in one function call?" yes, but you'll have to write the function : ) Commented Nov 3, 2011 at 12:03
  • @BorisGuéry, I meant built-in functions :-) Commented Nov 3, 2011 at 12:08
  • 3
    P.S: I'm aware I can write foreach($users as $user) {$ids[] = $user['id'];} in one line! but you know what I mean/need :-) Commented Nov 3, 2011 at 12:08
  • @Eugene, I need the array for other things obviously. And again, this is only for fun and learning new shorthands in PHP. Commented Nov 3, 2011 at 12:12

4 Answers 4

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360

Since PHP 5.5, you can use array_column:

$ids = array_column($users, 'id');

This is the preferred option on any modern project. However, if you must support PHP<5.5, the following alternatives exist:

Since PHP 5.3, you can use array_map with an anonymous function, like this:

$ids = array_map(function ($ar) {return $ar['id'];}, $users);

Before (Technically PHP 4.0.6+), you must create an anonymous function with create_function instead:

$ids = array_map(create_function('$ar', 'return $ar["id"];'), $users);
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7 Comments

nice, now if there's a native function that is similar to function ($ar) {return $ar['id'];} return value of key that would be awesome! :-)
well, that's not a "all in one" function, but Closure (Anynonymous functions) are a very powerfull concept that may be used for such processing, you'll rather like to know how to use them.
What if I want to get the key too? Suppose : $arr = [ 'ball'=>[ 'basket'=>5 ] ]; I want to get : $ball = ['ball'=>5];
@Angger Then you have a different question than this one. Feel free to ask it as long as you mention in detail what behavior you expect, for instance what should result if the input is ['ball' => ['golf' => 7, 'basket' => 5, 'soccer' => 6], 'shuttle' => ['badminton' => 1]].
Since PHP7.4 you can use array_map with an arrow function: $ids = array_map(fn ($ar) => $ar['id'], $users);
|
17

PHP 5.5+

Starting PHP5.5+ you have array_column() available to you, which makes all of the below obsolete.

PHP 5.3+

$ids = array_map(function ($ar) {return $ar['id'];}, $users);

Solution by @phihag will work flawlessly in PHP starting from PHP 5.3.0, if you need support before that, you will need to copy that wp_list_pluck.

PHP < 5.3

Wordpress 3.1+

In Wordpress there is a function called wp_list_pluck If you're using Wordpress that solves your problem.

PHP < 5.3

If you're not using Wordpress, since the code is open source you can copy paste the code in your project (and rename the function to something you prefer, like array_pick). View source here

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Comments

2

If id is the first key in the array, this'll do:

$ids = array_map('current', $users);

You should not necessarily rely on this though. :)

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Comments

-1

You can also use array_reduce() if you prefer a more functional approach

For instance: 

$userNames = array_reduce($users, function ($carry, $user) {
    array_push($carry, $user['name']);
    return $carry;
}, []);

Or if you like to be fancy,

$userNames = [];
array_map(function ($user) use (&$userNames){
    $userNames[]=$user['name'];
}, $users);

This and all the methods above do loop behind the scenes though ;)

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1 Comment

Your first example will not return an array, just the last value found for $user['name'] in the array. You need to push/append to the $carry and return the $carry as you go.

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