Sorting multidimensional array, upper case being sorted before lowercase

Question

Using the below for sorting a multidimensional array by screen name:

$sortArray = array();

foreach($members as $member){
    foreach($member as $key=>$value){
        if(!isset($sortArray[$key])){
            $sortArray[$key] = array();
        }
        $sortArray[$key][] = $value;
    }
}

$orderby = "screen_name";

array_multisort($sortArray[$orderby],SORT_ASC,$members);

But uppercase is being sorted before lowercase:

Allan Brenda Greg works

But Frank comes before dan

There's a lot out there on sorting arrays, but I finally got this working using the above, wanted to see if there was an easy way to fix it?

maček · Accepted Answer · 2012-05-01 22:13:54Z

uasort() should work for you

<?php

// custom sort function
function sort_by_screen_name($a, $b) {

    // compare using lowercase strings only
    $a = strtolower($a['screen_name']);
    $b = strtolower($b['screen_name']);

    if ($a == $b) {
        return 0;
    }

    return ($a < $b) ? -1 : 1;
}

$members = array(
    array('screen_name'=>'Greg'),
    array('screen_name'=>'Allen'),
    array('screen_name'=>'dan'),
    array('screen_name'=>'Brenda'),
);

// uasort() like a boss!
uasort($members, 'sort_by_screen_name');

print_r($members);

Output

Array
(
    [1] => Array
        (
            [screen_name] => Allen
        )

    [3] => Array
        (
            [screen_name] => Brenda
        )

    [2] => Array
        (
            [screen_name] => dan
        )

    [0] => Array
        (
            [screen_name] => Greg
        )

)

Note: the original array keys are preserved using this method. If you'd like the keys to be rewritten, you can simply use usort().

Sampson · Accepted Answer · 2012-05-01 22:29:39Z

1

You can sort this with usort() and a custom sorting function. You can modify this data if you like to see how it suits your own custom details: http://codepad.org/b89HwmbM

$members = array(
  array( "loc" => "Ontario",   "first" => "Bob",  "screen_name" => "fooArt" ),
  array( "loc" => "Atlanta",   "first" => "Sal",  "screen_name" => "TIMMY!" ),
  array( "loc" => "Panama",    "first" => "Mick", "screen_name" => "Analog" ),
  array( "loc" => "Pensacola", "first" => "A",    "screen_name" => "Franky" ),
  array( "loc" => "McPherson", "first" => "Anna", "screen_name" => "annie9" )
);

usort( $members, 'custom_sort' );

function custom_sort( $m1, $m2 ){
  return strtolower( $m1['screen_name'] ) > strtolower( $m2['screen_name'] );
};

The output from this sorting method follows:

Array
(
    [0] => Array
        (
            [loc] => Panama
            [first] => Mick
            [screen_name] => Analog
        )

    [1] => Array
        (
            [loc] => McPherson
            [first] => Anna
            [screen_name] => annie_23
        )

    [2] => Array
        (
            [loc] => Ontario
            [first] => Bob
            [screen_name] => fooArt
        )

    [3] => Array
        (
            [loc] => Pensacola
            [first] => A
            [screen_name] => Franky
        )

    [4] => Array
        (
            [loc] => Atlanta
            [first] => Sal
            [screen_name] => TIMMY!
        )

)

edited May 1, 2012 at 22:29

answered May 1, 2012 at 22:10

Sampson

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1 Comment

maček Over a year ago

This doesn't really help demonstrate usort's ability to handle multidimensional arrays.

mickmackusa · Accepted Answer · 2024-04-29 06:12:36Z

0

It is not necessary to mutate the strings before comparing them. Just compare the column values case-insensitively with strcasecmp(). (Demo)

$members = [
    ['screen_name'=>'Greg'],
    ['screen_name'=>'Allen'],
    ['screen_name'=>'dan'],
    ['screen_name'=>'Brenda'],
];

uasort($members, fn($a, $b) => strcasecmp($a['screen_name'], $b['screen_name']));

var_export($members);

If you don't need to preserve the original first level keys, then array_multisort() can do this task with no iterated function calls. (Demo)

array_multisort(array_column($members, 'screen_name'), SORT_STRING | SORT_FLAG_CASE, $members);

var_export($members);

answered Apr 29, 2024 at 6:12

mickmackusa♦

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