Sorting array in PHP based on another array indexes

Question

I have two arrays

// array of objects
$records = array(
  [0] => (object) [
             'id' => 1, //  (*)
             ....
        ],
  [1] => (object) [
            'id' => 2, //  (*)
             ....
        ],
   [2] => (object) [
            'id' => 3, //  (*)
             ....
        ],
);

// array 2
// the keys in this array refer to the object ids (*)
$sorted = array(
    '2'  => 7,
    '3'  => 4,
    '1'  => 2,
);

$new_records = array();

What I want to do is to sort the values of first array (i.e the objects) based on the order of the key index of the second array, so the end result in this case will become:

 $new_records = array(
      [0] => (object) [
                 'id' => 2,
                 ....
            ],
      [1] => (object) [
                'id' => 3,
                 ....
            ],
       [2] => (object) [
                'id' => 1,
                 ....
            ],
    );

$records = $new_records;

score 0 · Answer 1 · edited Apr 21 '18 at 05:51

0

Code: (Demo)

$records = [(object)['id' => 1], (object)['id' => 2], (object)['id' => 3]];
$sorted = ['2' => 7, '3' => 4, '1' => 2];

$tempArr = array();
foreach ($records as $value) {
     $tempArr[$value->id] = $value;
}
$resultArr = array_values(array_replace($sorted, $tempArr));

var_export($resultArr);

Output:

array (
  0 => 
  stdClass::__set_state(array(
     'id' => 2,
  )),
  1 => 
  stdClass::__set_state(array(
     'id' => 3,
  )),
  2 => 
  stdClass::__set_state(array(
     'id' => 1,
  )),
)

edited Apr 21 '18 at 05:51

mickmackusa

43,625
12
83
136

answered Jun 14 '17 at 12:57

Quang Minh

116
2

I have tidied up your code block and removed the useless "Try this" and "Good luck" texts that have no place in any answer. Please honor StackOverflow by adding an explanation to this post that will educate the OP and future researchers. – mickmackusa Apr 21 '18 at 05:51

score 0 · Accepted Answer · answered Jun 14 '17 at 13:01

0

Try this

$new_records = array();
foreach( $sort as $id => $pos ) {
    foreach( $records as $record ) {
        if( $record[ 'id' ] == $id ) {
            $new_records[] = $record;
            break;
        }
    }
}

answered Jun 14 '17 at 13:01

A. Blub

792
1
5
10

Your code works. But I think your code have a performance problem with a nested for loop. Try my code with 1 for and 1 function array_replace. – Quang Minh Jun 14 '17 at 13:07

score 0 · Answer 3 · answered Jun 14 '17 at 13:06

0

This make the job

$records = array(
   0 => (object) [
             'id' => 1, //  (*)
        ],
   1 => (object) [
            'id' => 2, //  (*)
        ],
   2 => (object) [
            'id' => 3, //  (*)
        ],
);

// array 2
// the keys in this array refer to the object ids (*)
$sorted = array(
    '2'  => 7,
    '3'  => 4,
    '1'  => 2,
);

$keySorted = array_keys($sorted);

usort($records, function ($a, $b) use ($keySorted) {

    $pos_a = array_search($a->id, $keySorted);
    $pos_b = array_search($b->id, $keySorted);
    return $pos_a - $pos_b;
});

var_dump($records);

answered Jun 14 '17 at 13:06

fxlacroix

557
4
18

This is a good / direct approach. Please improve your answer by explaining how your code block works. Remember, not every developer is familiar with the syntax of `usort()` and anonymous functions with a `use` argument. Explain what kinds of values are generated from `array_search()` including the flow-on effect of a `false` return value being used in the subtraction line. Always, always, always explain every answer that you post. Thank you for caring for StackOverflow. – mickmackusa Apr 21 '18 at 05:59
...very similar to [this post from 5 years earlier](https://stackoverflow.com/a/11145568/2943403). – mickmackusa Apr 22 '18 at 11:47

score 0 · Answer 4 · answered Jun 14 '17 at 13:16

0

Here, I have created sorting of array and add to your array of object using current() and key() is from php.

$i = 0;
while ($value = current($sorted)) {

    $key = key($sorted); // get key from array 2
    $records[i]->array('id' => $key); // set key to array of object

    next($array);
    $i++;
}

I hope this may help you.

answered Jun 14 '17 at 13:16

Harshil Dholakiya

105
11

This answer does not work. Proof: https://3v4l.org/TOGt1 It has typos, but even after correcting them, the new record declaration damages the input data that needs to be retained. Please fix or delete this answer. – mickmackusa Apr 21 '18 at 06:04

Sorting array in PHP based on another array indexes

4 Answers4