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);
natcasesort
(PHP 4, PHP 5, PHP 7, PHP 8)
natcasesort — 大文字小文字を区別しない"自然順"アルゴリズムを用いて配列をソートする
説明
natcasesort() は、大文字小文字を区別しないバージョンの natsort() です。
この関数は、人間が行うような手法でアルファベットまたは数字の文字列の順番を キー/値の関係を保持したままソートします。 これは、"自然順(natural ordering)"と呼ばれているものです。
注意:
比較結果が等しくなる二つの要素があった場合、それらの並び順は保持されます。PHP 8.0.0 より前のバージョンでは、ソートした配列におけるそれらの並び順は不定でした。
注意:
この関数をコールすると、配列の内部ポインタは最初の要素にリセットされます。
パラメータ
-
array -
入力の配列。
戻り値
常に true を返します。
例
例1 natcasesort() の例
<?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);
?>上の例の出力は以下となります。
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
)
より詳細な情報については、Martin Poolの » Natural Order String Comparison ページを参照ください。
参考
- natsort() - "自然順"アルゴリズムで配列をソートする
- 配列ソート関数の比較
- strnatcmp() - "自然順"アルゴリズムにより文字列比較を行う
- strnatcasecmp() - "自然順"アルゴリズムにより大文字小文字を区別しない文字列比較を行う
add a note
User Contributed Notes 6 notes
dslicer at maine dot rr dot com ¶
21 years ago
w-dot-rosenbach-at-netskill-de ¶
13 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>';
?>
claude at schlesser dot lu ¶
15 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 $result_arr;
}
?>
Hope it will be useful to somebody :)
vbAlexDOSMan at Yahoo dot com ¶
21 years ago
Ulli at Stemmeler dot net: I remade your function -- it's a little more compact now -- Enjoy...
function ignorecasesort(&$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($this));
}
}
shawn at shawnwilkerson dot com ¶
15 years ago
I kept getting varied results using natcasesort and sort on mixed arrays -- per the descriptions.
Sometimes simple is better:
A little snippet of code:
<?php if($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($r);
}
?>
I simply created a lower cased sort field at the front of the result set and then sort by it -- which provides the expected result and leaves the actual needed fields unchanged.
For the curious: all user information is kept completed in another database (and table) from the content database due to security reasons. The getUser functions we have written allow us to pull only what is legally allowed without exposing anything else.
This is why a left join or something wasn't used and we have to build a pseudo result array here from both databases.
tmiller25 at hotmail dot com ¶
22 years ago
add this loop to the function above if you want items which have the same first characters to be listed in a way that the shorter string comes first.
--------------------
/* short before longer (e.g. 'abc' should come before 'abcd') */
for($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;
}
}
--------------------
