Sort rows of a multidimensional array by column value with a sticky first row when a particular value is found

Question

My multidimensional array is sorted alphabetically by the OwnerNickName field, but I need to make the OwnerNickName = 'My House' row as the sticky first row and then everything else sorted by OwnerNickname ascending.

Input:

[
    '0318B69D-5DEB-11DF-9D7E-0026B9481364' => [
        'OwnerNickName' => 'andy',
        'Rooms' => [ /* irrelevant */ ]
    ],
    '286C29DE-A9BE-102D-9C16-00163EEDFCFC' => [
        'OwnerNickName' => 'anton',
        'Rooms' => [ /* irrelevant */ ]
    ],
    '8BE18F84-AC22-102D-9C16-00163EEDFCFC' => [
        'OwnerNickName' => 'mike',
        'Rooms' => [ /* irrelevant */ ]
    ],
    '29B455DE-A9BC-102D-9C16-00163EEDFCFC' => [
        'OwnerNickName' => 'My House',
        'Rooms' => [ /* irrelevant */ ]
    ]
]

Do you need to permanently rearrange the array? Or is the sort order variable? — dnagirl
– dnagirl, Commented Jun 2, 2010 at 12:25
Related: Custom rows of a 2d array by multiple columns with one row "sticky" in last position and Sort array by keys ascending and nominate a "sticky" key to be first — mickmackusa
– mickmackusa ♦, Commented Jan 23, 2024 at 6:59

nuqqsa · Accepted Answer · 2010-06-02 12:27:24Z

5

You may want to implement your own sorting function, e.g.:

function cmp($a, $b)
{
    if ($a['OwnerNickName'] == $b['OwnerNickName']) {
        return 0;
    }
    if ($a['OwnerNickName'] == 'My House') {
        return -1;
    } else if ($b['OwnerNickName'] == 'My House') {
        return 1;
    }
    return ($a['OwnerNickName'] < $b['OwnerNickName']) ? -1 : 1;
}    
usort($array, 'cmp');

answered Jun 2, 2010 at 12:27

nuqqsa

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1 Comment

Serty Oan Over a year ago

Maybe use uasort if you want to keep your keys

dnagirl · Accepted Answer · 2010-06-02 16:49:18Z

If you want to change your mind about which index to sort on or which value should be special, something like this might suit:

function specialSort(array &$array, $index, $specialvalue){
    $callback = function($a,$b) use ($index, $specialvalue) {  //closure
       if ($a[$index] == $b[$index]) return 0;
       if ($a[$index] == $specialvalue) return -1;
       if ($b[$index] == $specialvalue) return 1;
       return ($a[$index] < $b[$index]) ? -1 : 1;
    }  ;

    uasort($array, $callback);
}

$arr=array(
    'a'=>array('thing'=>'yay','who'=>'owee'),
    'foo'=>array('thing'=>'boo','who'=>'wik'),
    'd'=>array('thing'=>'kil','who'=>'ilo'),
    'b'=>array('thing'=>'ser','who'=>'uyt'),
    'zed'=>array('thing'=>'efv','who'=>'qet')
);

specialSort($arr,'who','ilo');
print_r($arr);

Gives the result:

Array
(
    [d] => Array
        (
            [thing] => kil
            [who] => ilo //special value
        )

    [a] => Array
        (
            [thing] => yay
            [who] => owee
        )

    [zed] => Array
        (
            [thing] => efv
            [who] => qet
        )

    [b] => Array
        (
            [thing] => ser
            [who] => uyt
        )

    [foo] => Array
        (
            [thing] => boo
            [who] => wik
        )

)

mickmackusa · Accepted Answer · 2024-01-23 07:23:45Z

0

To preserve the original first level keys, uasort(). Pass the sorting rules to the callback as two-element arrays to be compared by the spaceship operator. Because false is "less than" true, check if the OwnerNickName is NOT equal to My House to make it the sticky first element.

Code: (Demo)

uasort(
    $array,
    fn($a, $b) => [$a['OwnerNickName'] !== 'My House', $a['OwnerNickName']]
                  <=>
                  [$b['OwnerNickName'] !== 'My House', $b['OwnerNickName']]
);
var_export($array);

answered Jan 23, 2024 at 7:23

mickmackusa♦

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