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How to compare the size of strings in PHP?

怪我咯Original: 2017-05-10 17:34:492457browse

In WEB project development, it is often necessary to determine the size between two or more strings. However, we cannot determine the size of two strings by looking at two characters. So how to determine the size of two or more strings? As for the sizes of multiple strings, this article will take you through, How to compare the sizes of strings?

First we learn two functions strcmp() and strcasecmp() functions

These two functions are used to compare two The size of the string, their syntax is as follows:

strcmp(str1,str2)

strcasecmp(str1,str2)

These two functions are based on (ASCII code value) comparison of the size of the two strings, if str1>str2 returns 1; if str1< ;Str2 returns -1; if str1=str2, returns 0. The difference between them is that the function strcasecmp() is not case-sensitive during the comparison process, while the function strcmp() is case-sensitive during the comparison process.

Application Example

The strcasecmp() function and strcmp() function are used below to compare string sizes.

The code is as follows:

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>字符串大小写转换</title>
</head>
<body>
<form method="post" action="" enctype="multipart/form-data">
    <p>
        字符串1:<input type="text" name="str1">
    </p>

    <p>
        字符串2:<input type="text" name="str2">
    </p>


    <input type="submit" name="sub" value="比较" />
</form>
</body>
</html>
<?PHP
header("content-type:text/html;charset=utf-8");
$str1=$_POST[&#39;str1&#39;];
$str2=$_POST[&#39;str2&#39;];

if($_POST[&#39;sub&#39;]){
 $result=strcmp($str1,$str2);
 if($result==1){
 echo "<div>字符串&#39;".$str1."&#39; > 字符串&#39;".$str2."&#39;</div>";
    }
 if($result==0){
 echo "<div>字符串&#39;".$str1."&#39; = 字符串&#39;".$str2."&#39;</div>";
    }
 if($result==-1){
 echo "<div>字符串&#39;".$str1."&#39; < 字符串&#39;".$str2."&#39;</div>";
    }
}
?>

The result of running the code is as follows:

How to compare the size of strings in PHP?

The above example uses the strcmp() function to compare two characters String, if you are interested, you can replace the strcmp() function with the strcasecmp() function to try and see what the difference is.

How to compare the size of strings in PHP? Comparing the size of strings mainly focuses on comparing types and cases. In actual applications, when encountering the same English word, if its case is different, the operation result will be changed. If an error occurs, you can compare the strings first and then take the next step according to the situation.

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