php - Sort array of strings which may containing day and abbreviated month names

Solution:

You should use usort() to implement your own comparison function which first compares two strings without any numbers (use preg_replace('/\d+/', '', $str) for this), and then, if the two strings compared as equal, use strnatcmp() to compare the strings (including numbers) in a natsort() way.

usort($array, function($a, $b) {
    $cmp = strcmp(preg_replace('/\d+/', '', $a), preg_replace('/\d+/', '', $b));
    if ($cmp) {
        return $cmp;
    } else {
        return strnatcmp($a, $b);
    }
});
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Solution:

Oddly, it seems my interpretation of the required sorting logic is more in-depth than the asker's.

I see the rules as:

1. Sort by the first word, then if a tie,
2. If a "Feedback..." string, then parse the string and sort by month, then by day, then if still a tie,
3. Sort on the full string "naturally" and case-insensitively.

Code: (Demo)

$array = [
    "Feedback 13 okt",
    "Feedback 11 okt",
    "Feedback 12 okt",
    "Sweet",
    "Feedback 9 okt",
    "Feedback 6 okt",
    "Feedback 8 jun",
    "Fixes",
    "Realisation",
    "Feedback 22 mar",
    "Do something",
    "Feedback 3 maj",
    "Feedback 1 dec",
];

$mmm = array_flip([
    "jan", "feb", "mar", "apr",
    "maj", "jun", "jul", "aug",
    "sep", "okt", "nov", "dec"
]);

usort(
    $array,
    fn($a, $b) =>
        strtok($a, ' ') <=> strtok($b, ' ')

        ?: (sscanf($a, "Feedback %d %s", $aDay, $aMon)
            ? [$mmm[$aMon] ?? 13, $aDay]
            : [13, 32])
           <=>
           (sscanf($b, "Feedback %d %s", $bDay, $bMon)
            ? [$mmm[$bMon] ?? 13, $bDay]
            : [13, 32])

        ?: natcasecmp($a, $b)
);
var_export($array);
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Output:

array (
  0 => 'Do something',
  1 => 'Feedback 22 mar',
  2 => 'Feedback 3 maj',
  3 => 'Feedback 8 jun',
  4 => 'Feedback 6 okt',
  5 => 'Feedback 9 okt',
  6 => 'Feedback 11 okt',
  7 => 'Feedback 12 okt',
  8 => 'Feedback 13 okt',
  9 => 'Feedback 1 dec',
  10 => 'Fixes',
  11 => 'Realisation',
  12 => 'Sweet',
)
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By using the "Elvis operator" (?:), subsequent tiebreaker processes are only executed if necessary. This is best practice and offers best performance.

Alternate syntax for the above approach leveraging the$mmm lookup array: (Demo)

usort(
    $array,
    function($a, $b) use($mmm) {
        sscanf("$a 32 dec", "%[^0-9] %d %s", $aWord, $aDay, $aMon);
        sscanf("$b 32 dec", "%[^0-9] %d %s", $bWord, $bDay, $bMon);
        return [$aWord, $mmm[$aMon], $aDay] <=> [$bWord, $mmm[$bMon], $bDay];
    }
);
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If comfortable with regex, make a single pass over the array to make a modified version of the strings which can be sorted naturally (again leveraging the$mmm lookup array).

Code: (Demo)

array_multisort(
    preg_replace_callback(
        '/(.+) (\d+?) ([a-z]{3}?)/',
        fn($m) => "{$m[1]} {$mmm[$m[3]]} {$m[2]}",
        $array
    ),
    SORT_NATURAL,
    $array
);
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Solution:

You can create aDateTime from the date part and sort the dated entries chronologically inusort. I was not able to get my locale settings right to work with your language so I had to edit the data to use English month abbreviations. I assume you have your PHP properly configured for your locale so this should work on your system with your data.

usort($array, function($a, $b) { 
  $pattern = '/^\w*\s+/'; // ("Feedback ") matches first word + whitespaces
  $fmt = 'j M';
  $a_date = DateTime::createFromFormat($fmt, preg_replace($pattern, '', $a));
  $b_date = DateTime::createFromFormat($fmt, preg_replace($pattern, '', $b));
  if($a_date && $b_date) // both are dates
    return $a_date <=> $b_date;
  // fallback to compare as strings
  return strcmp($a, $b);
});
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So with the following$array value:

$array = [
    "Feedback 13 oct",
    "Feedback 11 oct",
    "Feedback 12 oct",
    "Sweet",
    "Feedback 9 oct",
    "Feedback 6 oct",
    "Feedback 8 jun",
    "Fixes",
    "Realisation",
    "Feedback 22 mar",
    "Do something",
    "Feedback 3 may",
    "Feedback 1 dec",
];
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After calling theusort function abovevar_export($array); will output the following:

array (
  0 => 'Do something',
  1 => 'Feedback 22 mar',
  2 => 'Feedback 3 may',
  3 => 'Feedback 8 jun',
  4 => 'Feedback 6 oct',
  5 => 'Feedback 9 oct',
  6 => 'Feedback 11 oct',
  7 => 'Feedback 12 oct',
  8 => 'Feedback 13 oct',
  9 => 'Feedback 1 dec',
  10 => 'Fixes',
  11 => 'Realisation',
  12 => 'Sweet',
)
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See it working here: https://onlinephp.io/c/dc5d6