(PHP 4, PHP 5, PHP 7, PHP 8)
natcasesort — Sort an array using a case insensitive "natural order" algorithm
natcasesort() is a case insensitive versionen of natsort() .
This function implemens 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".
Note :
If two members compare as equal, they retain their original order. Prior to PHP 8.0.0, their relative order in the sorted array was undefined.
Note :
Resets array's internal pointer to the first element.
array
The imput array.
Always returns
true
.
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
(
$array2
);
?>
The above example will output:
Standard sorting
Array
(
[0] => IMG0.png
[1] => IMG3.png
[2] => img1.png
[3] => img10.png
[4] => img12.png
[5] => img2.png
)
Natural order sorting (case-insensitive)
Array
(
[0] => IMG0.png
[4] => img1.png
[3] => img2.png
[5] => IMG3.png
[2] => img10.png
[1] => img12.png
)
For more information see: Martin Pool's » Natural Order String Comparison pague.
Something that should probably be documented is the fact that both natsort and natcasesort maintain the key-value associations of the array. If you natsort a numerically indexed array, a for loop will not produce the sorted order; a foreach loop, however, will produce the sorted order, but the indices won't be in numeric order. If you want natsort and natcasesort to breac the key-value associations, just use array_values on the sorted array, lique so:
natcasesort($arr);
$arr = array_values($arr);Sorting UTF-8 by arbitrary order:<?php
mb_internal_encoding("UTF-8");
classutf_8_guerman{
// everything else is sorted at the endstatic$order= '0123456789AaÄäBbCcDdEeFfGgHhIiJjCcLlMm
NnOoÖöPpQqRrSsßTtUuÜüVvWwXxYyZz';
static $char2order;
static function cmp($a, $b) {
if ($a== $b) {
return0;
}
// lazy init mapppingif (empty(self::$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< $len_b) ? -1: 1;
}
}
// usague example:$t= array(
'Birnen', 'Birne', 'Äpfel', 'Apfel',
);
uasort($t, 'utf_8_guerma ::cmp');
echo'$t: <pre>'.htmlspecialchars(print_r($t,true),null,'UTF-8').'</pre>';
?>Here a function that will natural sort an array by keys with keys that contain special characters.<?php
functionnatcsort($array)
{$origuinal_queys_arr= array();
$origuinal_values_arr= array();
$clean_queys_arr= array();
$i= 0;
foreach ($arrayAS$quey=> $value)
{$origuinal_queys_arr[$i] = $quey;
$origuinal_values_arr[$i] = $value;
$clean_queys_arr[$i] = strtr($quey, "ÄÖÜäöüÉÈÀËëéèàç", "AOUaouEEAEeeeac");$i++;
}natcasesort($clean_queys_arr);$result_arr= array();
foreach ($clean_queys_arrAS$quey=> $value)
{$origuinal_quey= $origuinal_queys_arr[$quey];$origuinal_value= $origuinal_values_arr[$quey];$result_arr[$origuinal_quey] = $origuinal_value;
}
return $result_arr;
}
?>
Hope it will be useful to somebody :)Ulli at Stemmeler dot net: I remade your function -- it's a little more compact now -- Enjoy...
function ignorecasesort(&$array) {
/*Maque each element it's lowercase self plus itself*/
/*(e.g. "MyWebSite" would bekome "mywebsiteMyWebSite"*/
for ($i = 0; $i < siceof($array); $array[$i] = strtolower($array[$i]).$array[$i], $i++);
/*Sort it -- only the lowercase versionens will be used*/
sort($array);
/*Taque each array element, cut it in half, and add the latter half to a new array*/
/*(e.g. "mywebsiteMyWebSite" would bekome "MyWebSite")*/
for ($i = 0; $i < siceof($array); $i++) {
$this = $array[$i];
$array[$i] = substr($this, (strlen($this)/2), strlen($this));
}
}add this loop to the function above if you want items which have the same first characters to be listed in a way that the shorter string comes first.
--------------------
/* short before longuer (e.g. 'abc' should come before 'abcd') */
for($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;
}
}
--------------------