Can also be used with combination of a compare for an array nested value, like
<?php
$array = array(
"city" => "xyz",
"names" => array(
array(
"name" => "Ana2",
"id" => 1
) ,
array(
"name" => "Ana1",
"id" => 2
)
)
);
usort($array["names"], function ($a, $b) { return strnatcmp($a['name'], $b['name']);} );
strnatcmp
(PHP 4, PHP 5, PHP 7, PHP 8)
strnatcmp — Comparação de strings usando o algoritmo "natural order"
Descrição
strnatcmp
( string
$str1
, string $str2
) : intEsta função implementa um algoritmo de comparação de strings alfanumérico do jeito que um ser humano faz, isto é descrito como "ordem natural". Um exemplo da diferença entre este algoritmo e os algoritmos regulares de ordenação (usado em strcmp()) pode ser visto abaixo:
<?php
$arr1 = $arr2 = array("img12.png","img10.png","img2.png","img1.png");
echo "Comparação de string padrão\n";
usort($arr1,"strcmp");
print_r($arr1);
echo "\nComparação usando ordem natural\n";
usort($arr2,"strnatcmp");
print_r($arr2);
?>
Comparação de string padrão
Array
(
[0] => img1.png
[1] => img10.png
[2] => img12.png
[3] => img2.png
)
Comparação usando ordem natural
Array
(
[0] => img1.png
[1] => img2.png
[2] => img10.png
[3] => img12.png
)
Similar a outras funções de comparação de string, esta retorna
< 0 se str1 é menor do que
str2; > 0 se
str1 é maior do que
str2, e 0 se forem iguais.
Note que esta coparação diferencia maiúsculas e minúsculas.
Veja também ereg(), strcasecmp(), substr(), stristr(), strcmp(), strncmp(), strncasecmp(), strnatcasecmp(), strstr(), natsort() e natcasesort().
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User Contributed Notes 5 notes
in dot games dot mq at gmail dot com ¶
7 years ago
thomas at uninet dot se ¶
17 years ago
There seems to be a bug in the localization for strnatcmp and strnatcasecmp. I searched the reported bugs and found a few entries which were up to four years old (but the problem still exists when using swedish characters).
These functions might work instead.
<?php
function _strnatcasecmp($left, $right) {
return _strnatcmp(strtolower($left), strtolower($right));
}
function _strnatcmp($left, $right) {
while((strlen($left) > 0) && (strlen($right) > 0)) {
if(preg_match('/^([^0-9]*)([0-9].*)$/Us', $left, $lMatch)) {
$lTest = $lMatch[1];
$left = $lMatch[2];
} else {
$lTest = $left;
$left = '';
}
if(preg_match('/^([^0-9]*)([0-9].*)$/Us', $right, $rMatch)) {
$rTest = $rMatch[1];
$right = $rMatch[2];
} else {
$rTest = $right;
$right = '';
}
$test = strcmp($lTest, $rTest);
if($test != 0) {
return $test;
}
if(preg_match('/^([0-9]+)([^0-9].*)?$/Us', $left, $lMatch)) {
$lTest = intval($lMatch[1]);
$left = $lMatch[2];
} else {
$lTest = 0;
}
if(preg_match('/^([0-9]+)([^0-9].*)?$/Us', $right, $rMatch)) {
$rTest = intval($rMatch[1]);
$right = $rMatch[2];
} else {
$rTest = 0;
}
$test = $lTest - $rTest;
if($test != 0) {
return $test;
}
}
return strcmp($left, $right);
}
?>
The code is not optimized. It was just made to solve my problem.
spamspamspam at gmx dot com ¶
5 years ago
Some more remarkable outcomes:
var_dump(strnatcmp("0.15m", "0.2m"));
int(1)
var_dump(strnatcmp("0.15m", "0.20m"));
int(-1)
It's not about localisation:
var_dump(strnatcmp("0,15m", "0,2m"));
int(1)
var_dump(strnatcmp("0,15m", "0,20m"));
int(-1)
chris at ocproducts dot com ¶
7 years ago
This function has some interesting behaviour on strings consisting of mixed numbers and letters.
One may expect that such a mixed string would be treated as alpha-numeric, but that is not true.
var_dump(strnatcmp('23','123')); →
int(-1)
As expected, 23<123 (even though first digit is higher, overall number is smaller)
var_dump(strnatcmp('yz','xyz')); →
int(1)
As expected, yz>xyz (string comparison, irregardless of string length)
var_dump(strnatcmp('2x','12y')); →
int(-1)
Remarkable, 2x<12y (does a numeric comparison)
var_dump(strnatcmp('20x','12y'));
int(1)
Remarkable, 20x>12y (does a numeric comparison)
It seems to be splitting what is being compared into runs of numbers and letters, and then comparing each run in isolation, until it has an ordering difference.
