PHP function strcmp() that compares two strings (case sensitive)-PHP Tutorial-php.cn

Example

Compare two strings (case sensitive):

<?php
echo strcmp("Hello world!","Hello world!");
?>

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Definition and usage

strcmp() function compares two string.

Note: The strcmp() function is binary safe and case-sensitive.

Tip: This function is similar to the strncmp() function, except that with strncmp() you can specify the number of characters for each string to be compared.

Syntax

strcmp(string1,string2)

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Parameters	Description
string1	Required. Specifies the first string to compare.
string2	Required. Specifies the second string to be compared.

Technical details

PHP version: 4+

更多实例

实例 1

比较两个字符串（区分大小写，Hello 和 hELLo 输出不相同）：

<?php
echo strcmp("Hello","Hello");
echo "<br>";
echo strcmp("Hello","hELLo");
?>

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实例 2

不同的返回值：

<?php
echo strcmp("Hello world!","Hello world!"); // the two strings are equal
echo strcmp("Hello world!","Hello"); // string1 is greater than string2
echo strcmp("Hello world!","Hello world! Hello!"); // string1 is less than string2 
?>

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以区分大小写的方式比较两个字符串
Strcmp()函数对两个字符串进行二进制安全的比较，并区分大小写。其形式为：
int strcmp ( string str1 , string str2 )
根据比较的结果将返回如下的一个可能值。
•如果str1 和str2 相等则返回0 。
•如果str1小于str2则返回-1 。
•如果str1大于str2则返回1 。
网站经常要求待注册的用户输入并确认他选择的密码，减少由于键入错误而生成不正确密码的可能性。因为密码通常是区分大小写的，所以strcmp()对于比较这两个密码是非常合适的：

<?php 
$pswd = "supersecret"; 
$pswd2 = "supersecret"; 
if (strcmp($pswd,$pswd2) != 0) 
echo "Your passwords do not match!"; 
else 
echo "Passwords match!"; 
?>

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注意，对于strcmp ( ) ，字符串必须完全匹配才认为是相等的。例如，Supersecret 不同于supersecret 。如果要以不区分大小写的方式比较两个字符串，可以考虑下面介绍的strcasecmp ()。
关于这个函数，另一个容易混淆的地方是：两个字符串相等时要返回0 。这与使用==操作符完成字符串比较有所不同，如下：
if ( $str1 = = $str2)
两种方式目标相同，都是比较两个字符串，但要记住，它们返回的值却不同。

实例代码：

<?php 
echo strcmp("Hello world!","Hello world!"); 
//返回0 
?>

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Related labels：

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Return value:	This function returns: 0 - if the two strings are equal ##<0 - if string1 is less than string2 >0 - if string1 Greater than string2