How to change the key in associative array php

Question

I have array like this:

Array (
   [0] => Aenean
   [1] => Lorem
   [2] => Morbi
)

I am try using foreach to make array above format be associative array. Trying to change the key (e.g. 0,1,2) to be another value (e.g. x,y,z).

array(
    'x' => 'Aenean',
    'y' => 'Lorem',
    'z' => 'Morbi'
),

So far, I try using foreach but give me wrong result

    $r_cat = array (Aenean,Lorem,Morbi);

    $cs = array();
    foreach ($r_cat as $c ) {
     $cs [] .= array (get_cat_ID($c) => $c);
    }
    print_r ($cs);

RESULT

Array (
   [0] => Array
   [1] => Array
   [2] => Array
)

`$cs [] .=` makes little sense to begin with, `.=` is for string concatenation. `$cs[] =` would be the correct way to add new entries to a numeric array - but you want to specify the associative key here, so you must actually do that - `$cs['somekey'] =` — misorude, Dec 04 '18 at 08:33
Related: [Replace keys in an array based on another lookup/mapping array](https://stackoverflow.com/a/71274431/2943403) — mickmackusa, Apr 17 '23 at 21:25

score 4 · Accepted Answer · answered Dec 04 '18 at 08:37

4

You can use array_reduce

$array = ['Aenean', 'Lorem', 'Morbi'];

$array = array_reduce($array, function($carry, $item) {
    $carry[get_cat_ID($item)] = $item;

    return $carry;
}, []);

var_dump($array);

answered Dec 04 '18 at 08:37

Mihai Matei

24,166
5
32
50

score 1 · Answer 2 · edited Dec 04 '18 at 08:49

1

You can use PHP array_combine() function to set key from one array and values from the second array. No need to use the loop :

$a = array('x','y','z');
$b = array('Aenean','Lorem','Morbi');
$c = array_combine($a, $b);

echo '<pre>';print_r($c); echo '</pre>';

Result:

Array
(
    [x] => Aenean
    [y] => Lorem
    [z] => Morbi
)

edited Dec 04 '18 at 08:49

treyBake

6,440
6
26
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answered Dec 04 '18 at 08:44

Manoj Singh

253
1
7

score 0 · Answer 3 · answered Dec 04 '18 at 08:37

<?php
$array = array(
    0 => 'Aenean',
    1 => 'Lorem',
    2 => 'Morbi'
);

$i = 0;

$keyValues = array('x','y','z');

foreach ($array as $key => $value) {
    $cs[$keyValues[$i]] = $value;
    $i++;
}

echo '<pre>';
print_r($cs);

And the output is :

Array
(
    [x] => Aenean
    [y] => Lorem
    [z] => Morbi
)

I made a test array with some example values you want to put (x,y,z as you mentioned) and replaced your keys inside the foreach like you tried as well.

Another way is to use the key value in your foreach and replace it with the new one and after unset your old key like below:

<?php
$array = array(
    0 => 'Aenean',
    1 => 'Lorem',
    2 => 'Morbi'
);

$i = 0;

$keyValues = array('x','y','z');

foreach ($array as $key => $value) {
    $array[$keyValues[$i]] = $array[$key];
    unset($array[$key]);
    $i++;
}

echo '<pre>';
print_r($array);

How to change the key in associative array php

3 Answers3