Converting php array of arrays into single array

Question

I have an array whose values are all arrays of a specific format that looks like this:

Array
(
    [0] => Array
           (
               [username] => John
           )    
    [1] => Array
           (
               [username] => Joe
           )
    [2] => Array
           (
               [username] => Jake
           )
)

and I would like to have this:

Array
(
    [0] => John   
    [1] => Joe
    [2] => Jake
)

I can do this manually with a loop but is there a better way? If not, is it possible to do this for an array of objects that have a common attribute?

Community · Accepted Answer · 2023-11-17 20:38:18Z

45

Since PHP 5.5.0 there is a built-in function array_column which does exactly this.

edited Nov 17, 2023 at 20:38

CommunityBot

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answered Oct 31, 2013 at 17:47

Peter Taylor

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3 Comments

Léo Lam Over a year ago

If you're using PHP 5.3 or 5.4, you can always use this library (open-source).

Dinesh Over a year ago

How can i use array_column if i have no specific keys for my array. Its the default keys provided in php

xpoback Over a year ago

Since PHP 5.6 you can use: $newArray = array_merge(...$oldArray);

SilentGhost · Accepted Answer · 2010-02-18 14:56:16Z

33

why complicate things?

foreach($array as $k=>$v) {
    $new[$k] = $v['username'];
}

answered Feb 18, 2010 at 14:56

SilentGhost

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1 Comment

shikata Over a year ago

and this is faster than array_map()

xpoback · Accepted Answer · 2019-12-02 09:42:20Z

12

Since PHP 5.6 you can use the splat operator. In case array keys are numeric, you could use this:

$newArray = array_merge(...$oldArray);

edited Dec 2, 2019 at 9:42

answered Aug 7, 2019 at 13:54

xpoback

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Comments

Manoj Thapliyal · Accepted Answer · 2016-01-28 12:06:07Z

6

$new_array = array_column($last_array, 'username');

answered Jan 28, 2016 at 12:06

Manoj Thapliyal

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Comments

vfsoraki · Accepted Answer · 2018-04-24 20:17:03Z

5

For other readers, like myself, if the key username is different for each internal array, and you want to flatten it, use this:

call_user_func_array('array_merge', $the_array);

Note that the keys have to be different. Like this:

[
 0 => [
  'a' => 1
 ],
 1 => [
  'b' => 2
 ]
]

After running the code, you have this:

[
 'a' => 1,
 'b' => 2,
]

answered Apr 24, 2018 at 20:17

vfsoraki

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Comments

user32117 · Accepted Answer · 2010-02-18 15:05:48Z

2

If you're using PHP 5.3 you can make use of array_walk_recursive and a closure (the closure can be replaced by a normal function if your PHP version < 5.3):

function arrayFlatten(array $array) {
    $flatten = array();
    array_walk_recursive($array, function($value) use(&$flatten) {
        $flatten[] = $value;
    });

    return $flatten;
}

$nested = array(
    array('username' => 'John'),
    array('username' => 'Joe'),
    array('username' => 'Jake'),
);

$flattened = arrayFlatten($nested);

var_dump($flattened)

array
  0 => string 'John' (length=4)
  1 => string 'Joe' (length=3)
  2 => string 'Jake' (length=4)

answered Feb 18, 2010 at 15:05

user32117

1 Comment

user1794918 Over a year ago

The function arrayFlatten(array $array) should be arrayFlatten(array $nested).

thetaiko · Accepted Answer · 2010-02-18 15:08:44Z

0

$new = array_map(create_function('$auser', 'return $auser["username"];'), $array);

If using objects you could just change return $auser["username"]; to return $auser->get_username();

answered Feb 18, 2010 at 15:08

thetaiko

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Comments

random_user_name · Accepted Answer · 2012-11-14 14:18:58Z

0

Try this code:

foreach   ($arr as $key => $val)
{
    sort($val );
    $new = array_merge($val, $new);
}
print_r ($new);

edited Nov 14, 2012 at 14:18

random_user_name

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answered Feb 23, 2010 at 12:15

Pavunkumar

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Comments

William Buttlicker · Accepted Answer · 2014-02-12 10:33:19Z

0

Try this:

$list=array();
foreach($array as $v) {
    array_push($list, $v['username']);
}

edited Feb 12, 2014 at 10:33

William Buttlicker

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answered Feb 12, 2014 at 10:14

Nanhe Kumar

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Comments

MrUpsidown · Accepted Answer · 2015-04-09 09:45:57Z

0

If you don't care about the keys:

$new_array = array();

foreach($array as $v) {

    $new_array[] = $v['username']
}

answered Apr 9, 2015 at 9:45

MrUpsidown

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Comments

smarber · Accepted Answer · 2016-12-27 17:46:37Z

0

For those who're using composer:

if <=php5.5 array_column can be used
if >php5.5 available polyfills such as https://github.com/symfony/polyfill/tree/master/src/Php55 can be used. Once you composer install symfony/polyfill-php55, then you can just call array_column as if your php5.4 or below had it.

answered Dec 27, 2016 at 17:46

smarber

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