PHP 7.0.6 Released

    natcasesort

    (PHP 4, PHP 5, PHP 7)

    natcasesort — Sort an array using a case insensitive "natural order" algorithm

    Description

    bool natcasesort ( array &$array )

    natcasesort() is a case insensitive version of natsort().

    This function implements a sort algorithm that orders alphanumeric strings in the way a human being would while maintaining key/value associations. This is described as a "natural ordering".

    Parameters

    array

    The input array.

    Return Values

    Returns TRUE on success or FALSE on failure.

    Examples

    Example #1 natcasesort() example

    <?php
    $array1     = $array2 = array('IMG0.png', 'img12.png', 'img10.png', 'img2.png', 'img1.png', 'IMG3.png');

    sort($array1);
    echo     "Standard sorting\n";
    print_r($array1);

    natcasesort($array2);
    echo     "\nNatural order sorting (case-insensitive)\n";
    print_r($array2);
    ?>

    The above example will output:

    Standard sorting
Array
(
    [0] => IMG0.png
    [1] => IMG3.png
    [2] => img1.png
    [3] => img10.png
    [4] => img12.png
    [5] => img2.png
)

Natural order sorting (case-insensitive)
Array
(
    [0] => IMG0.png
    [4] => img1.png
    [3] => img2.png
    [5] => IMG3.png
    [2] => img10.png
    [1] => img12.png
)

    For more information see: Martin Pool's » Natural Order String Comparison page.

    See Also

    User Contributed Notes

    dslicer at maine dot rr dot com
    12 years ago
    Something that should probably be documented is the fact that both natsort and natcasesort maintain the key-value associations of the array. If you natsort a numerically indexed array, a for loop will not produce the sorted order; a foreach loop, however, will produce the sorted order, but the indices won't be in numeric order. If you want natsort and natcasesort to break the key-value associations, just use array_values on the sorted array, like so:

    natcasesort($arr);
    $arr = array_values($arr);
    w-dot-rosenbach-at-netskill-de
    5 years ago
    Sorting UTF-8 by arbitrary order:

    <?php
    mb_internal_encoding    ("UTF-8");

    class     utf_8_german
    {
          // everything else is sorted at the end
          static $order = '0123456789AaÄäBbCcDdEeFfGgHhIiJjKkLlMm
    NnOoÖöPpQqRrSsßTtUuÜüVvWwXxYyZz'    ;
      static     $char2order;
     
      static function     cmp($a, $b) {
        if (    $a == $b) {
            return     0;
        }
       
            // lazy init mapping
            if (empty(self::$char2order))
        {
              $order = 1;
              $len = mb_strlen(self::$order);
          for (    $order=0; $order<$len; ++$order)
          {
                self::$char2order[mb_substr(self::$order, $order, 1)] = $order;
          }
        }
       
            $len_a = mb_strlen($a);
            $len_b = mb_strlen($b);
            $max=min($len_a, $len_b);
        for(    $i=0; $i<$max; ++$i)
        {
              $char_a= mb_substr($a, $i, 1);
              $char_b= mb_substr($b, $i, 1);
         
          if (    $char_a == $char_b) continue;
              $order_a = (isset(self::$char2order[$char_a])) ? self::$char2order[$char_a] : 9999;
              $order_b = (isset(self::$char2order[$char_b])) ? self::$char2order[$char_b] : 9999;
         
          return (    $order_a < $order_b) ? -1 : 1;
        }
        return (    $len_a < $len_b) ? -1 : 1;
      }
    }

    // usage example:

    $t = array(
          'Birnen', 'Birne', 'Äpfel', 'Apfel',
    );

    uasort($t, 'utf_8_german::cmp');
    echo     '$t: <pre>'.htmlspecialchars(print_r($t,true),null,'UTF-8').'</pre>';
    ?>
    tmiller25 at hotmail dot com
    14 years ago
    add this loop to the function above if you want items which have the same first characters to be listed in a way that the shorter string comes first.
    --------------------
      /* short before longer (e.g. 'abc' should come before 'abcd') */
      for($i=count($array)-1;$i>0;$i--) {
        $str_a = $array[$i  ];
        $str_b = $array[$i-1];
        $cmp_a = strtolower(substr($str_a,0,strlen($str_a)));
        $cmp_b = strtolower(substr($str_b,0,strlen($str_a)));
        if ($cmp_a==$cmp_b && strlen($str_a)<strlen($str_b)) {
          $array[$i]=$str_b; $array[$i-1]=$str_a; $i+=2;
        }
      }
    --------------------
    claude at schlesser dot lu
    7 years ago
    Here a function that will natural sort an array by keys with keys that contain special characters.

    <?php
    function natksort($array)
    {
            $original_keys_arr = array();
            $original_values_arr = array();
            $clean_keys_arr = array();

            $i = 0;
        foreach (    $array AS $key => $value)
        {
                $original_keys_arr[$i] = $key;
                $original_values_arr[$i] = $value;
                $clean_keys_arr[$i] = strtr($key, "ÄÖÜäöüÉÈÀËëéèàç", "AOUaouEEAEeeeac");
                $i++;
        }

            natcasesort($clean_keys_arr);

            $result_arr = array();

        foreach (    $clean_keys_arr AS $key => $value)
        {
                $original_key = $original_keys_arr[$key];
                $original_value = $original_values_arr[$key];
                $result_arr[$original_key] = $original_value;
        }

        return     $result_arr;
    }
    ?>

    Hope it will be useful to somebody :)
    vbAlexDOSMan at Yahoo dot com
    12 years ago
    Ulli at Stemmeler dot net:  I remade your function -- it's a little more compact now -- Enjoy...

    function ignorecasesort(&$array) {

      /*Make each element it's lowercase self plus itself*/
      /*(e.g. "MyWebSite" would become "mywebsiteMyWebSite"*/
      for ($i = 0; $i < sizeof($array); $array[$i] = strtolower($array[$i]).$array[$i], $i++);

      /*Sort it -- only the lowercase versions will be used*/
      sort($array);

      /*Take each array element, cut it in half, and add the latter half to a new array*/
      /*(e.g. "mywebsiteMyWebSite" would become "MyWebSite")*/
      for ($i = 0; $i < sizeof($array); $i++) {
        $this = $array[$i];
        $array[$i] = substr($this, (strlen($this)/2), strlen($this));
      }
    }
    shawn at shawnwilkerson dot com
    6 years ago
    I kept getting varied results using natcasesort and sort on mixed arrays -- per the descriptions.

    Sometimes simple is better:

    A little snippet of code:

    <?php                        if($responders->num_rows) {
                                    $i=0;
                                while(    $row= $responders->fetch_assoc()) {
                                        $user=getUserName($row['responderID']);
                                        $r[$i]= array("sortname"=>strtolower($user),"userName"=>$user, "userID"=>$row['responderID'], "responderID"=>$row['idresponders']);
                                        $i++;
                                }
                                    sort($r);
                                    print_r($r);                           
                            }

    ?>

    I simply created a lower cased sort field at the front of the result set and then sort by it -- which provides the expected result and leaves the actual needed fields unchanged.

    For the curious:  all user information is kept completed in another database (and table) from the content database due to security reasons.  The getUser functions we have written allow us to pull only what is legally allowed without exposing anything else.

    This is why a left join or something wasn't used and we have to build a pseudo result array here from both databases.
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