String comparisons using a "natural order" algorithm_鑴氭湰瀛﹀爞

说明

int strnatcmp ( string $str1 , string $str2 )

This function implements a comparison algorithm that orders alphanumeric strings in the way a human being would, this is described as a "natural ordering". Note that this comparison is case sensitive.

参数

str1: The first string.
str2: The second string.

返回值

Similar to other string comparison functions, this one returns < 0 if str1 is less than str2 ; > 0 if str1 is greater than str2 , and 0 if they are equal.

范例

An example of the difference between this algorithm and the regular computer string sorting algorithms (used in strcmp()) can be seen below:


<?php
$arr1 = $arr2 = array("img12.png", "img10.png", "img2.png", "img1.png");
echo "Standard string comparison\n";
usort($arr1, "strcmp");
print_r($arr1);
echo "\nNatural order string comparison\n";
usort($arr2, "strnatcmp");
print_r($arr2);
?>

上例将输出：

Standard string comparison
Array
(
    [0] => img1.png
    [1] => img10.png
    [2] => img12.png
    [3] => img2.png
)

Natural order string comparison
Array
(
    [0] => img1.png
    [1] => img2.png
    [2] => img10.png
    [3] => img12.png
)

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

参见

preg_match() - 进行正则表达式匹配
strcasecmp() - Binary safe case-insensitive string comparison
substr() - Return part of a string
stristr() - Case-insensitive strstr
strcmp() - Binary safe string comparison
strncmp() - Binary safe string comparison of the first n characters
strncasecmp() - Binary safe case-insensitive string comparison of the first n characters
strnatcasecmp() - Case insensitive string comparisons using a "natural order" algorithm
strstr() - Find first occurrence of a string
natsort() - 用“自然排序”算法对数组排序
natcasesort() - 用“自然排序”算法对数组进行不区分大小写字母的排序