natcasesort
(PHP 4, PHP 5)
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($array2);
?>
The above example will output:
Standard sorting
Array
(
[0] => IMG0.png
[1] => IMG3.png
[2] => img1.png
[3] => img10.png
[4] => img12.png
[5] => img2.png
)
Natural order sorting (case-insensitive)
Array
(
[0] => IMG0.png
[4] => img1.png
[3] => img2.png
[5] => IMG3.png
[2] => img10.png
[1] => img12.png
)
For more information see: Martin Pool's » Natural Order String Comparison page.
See Also
- natsort() - Sort an array using a "natural order" algorithm
- The comparison of array sorting functions
- strnatcmp() - String comparisons using a "natural order" algorithm
- strnatcasecmp() - Case insensitive string comparisons using a "natural order" algorithm
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Коментарии
add this loop to the function above if you want items which have the same first characters to be listed in a way that the shorter string comes first.--------------------
/* short before longer (e.g. 'abc' should come before 'abcd') */
for($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; $i+=2;
}
}
--------------------
Something that should probably be documented is the fact that both natsort and natcasesort maintain the key-value associations of the array. If you natsort a numerically indexed array, a for loop will not produce the sorted order; a foreach loop, however, will produce the sorted order, but the indices won't be in numeric order. If you want natsort and natcasesort to break the key-value associations, just use array_values on the sorted array, like so:
natcasesort($arr);
$arr = array_values($arr);
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($this));
}
}
Here a function that will natural sort an array by keys with keys that contain special characters.
<?php
function natksort($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 :)
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>';
?>