Solve the problem of the same php strings but different lengths

Methods to solve the unequal lengths of PHP strings: first check the encoding methods of the two strings through the "mb_detect_encoding()" function; then check the specific character lengths; and finally remove non-Chinese characters.

Question:

As shown in the picture, there are two at first glance The same Chinese string "Logistics Support Department", but one has a length of 21 and the other has a length of 15.

First of all, you may intuitively think that it is caused by different encoding methods.
Use the mb_detect_encoding() function to check the encoding methods of the two strings. The code is as follows

<?phpheader("Content-Type: text/html;charset=utf-8"); 

$data[0]=$str1="后勤保障部‍";$data[1]=$str2="后勤保障部";
var_dump($data);//查看编码方式$encode1 = mb_detect_encoding($str1,  array("ASCII","UTF-8","GB2312","GBK","BIG5"));$encode2 = mb_detect_encoding($str2,  array("ASCII","UTF-8","GB2312","GBK","BIG5"));echo "str1=&#39;".$str1."&#39;"."&emsp;编码:".$encode1."</br>";echo "str2=&#39;".$str2."&#39;"."&emsp;编码:".$encode2."</br>";?>

But the output results are all UTF-8

So what is the reason? Let’s check the specific character length in the output

<?phpheader("Content-Type: text/html;charset=utf-8"); 

$data[0]=$str1="后勤保障部‍";$data[1]=$str2="后勤保障部";
var_dump($data);//查看编码方式$encode1 = mb_detect_encoding($str1,  array("ASCII","UTF-8","GB2312","GBK","BIG5"));$encode2 = mb_detect_encoding($str2,  array("ASCII","UTF-8","GB2312","GBK","BIG5"));//当mb_strlen的内码选择为UTF-8的时候，则会将中文字符当成一个字符//strlen,得到的是字符串所占的字节数echo "str1=&#39;".$str1."&#39;".":&emsp;字符长度:".mb_strlen($str1).":&emsp;字节长度:".strlen($str1)."&emsp;编码:".$encode1."</br>";echo "str2=&#39;".$str2."&#39;".":&emsp;字符长度:".mb_strlen($str2).":&emsp;字节长度:".strlen($str2)."&emsp;编码:".$encode2."</br>";?>

The output results are as follows:

It was found that the string str1 has 7 Chinese characters, but only 5 are actually displayed, which is the "Logistics Support Department"

By intercepting the last two characters of str1 Character view

//截取str1后面两个未显示字符$res=mb_substr($str1, 5,2);echo "最后两字符:".$res."</br>";echo mb_strlen($res);

cannot be echo displayed, but it does occupy two characters

If the strings that look the same are actually required to be equal, processing needs to be performed. The processing is to eliminate non-Chinese characters:

//剔除str1字串中未显示的字符（非中文字符）preg_match_all('/[\x{4e00}-\x{9fff}]+/u', $str1, $matches);$str1 = join('', $matches[0]);

The final code is as follows

<?phpheader("Content-Type: text/html;charset=utf-8"); 

$data[0]=$str1="后勤保障部‍";$data[1]=$str2="后勤保障部";
var_dump($data);//查看编码方式$encode1 = mb_detect_encoding($str1,  array("ASCII","UTF-8","GB2312","GBK","BIG5"));$encode2 = mb_detect_encoding($str2,  array("ASCII","UTF-8","GB2312","GBK","BIG5"));//当mb_strlen的内码选择为UTF-8的时候，则会将中文字符当成一个字符//strlen,得到的是字符串所占的字节数echo "str1=&#39;".$str1."&#39;".":&emsp;字符长度:".mb_strlen($str1).":&emsp;字节长度:".strlen($str1)."&emsp;编码:".$encode1."</br>";echo "str2=&#39;".$str2."&#39;".":&emsp;字符长度:".mb_strlen($str2).":&emsp;字节长度:".strlen($str2)."&emsp;编码:".$encode2."</br>";//截取str1后面两个未显示字符echo "</br>------------------截取str1后面两个未显示字符---------------------</br>";$res=mb_substr($str1, 5,2);echo "str1最后两字符:&emsp;".$res."</br>";echo "str1长度:&emsp;".mb_strlen($res)."</br>";//比较echo "</br>--------------------------相等比较----------------------------------</br>";echo "str1 与 str2比较:&emsp;";echo strcomp($str1,$str2)."</br>";echo "str2 与 str2比较:&emsp;";echo strcomp($str2,$str2)."</br>";//剔除str1字串中非中文preg_match_all(&#39;/[\x{4e00}-\x{9fff}]+/u&#39;, $str1, $matches);$str1 = join(&#39;&#39;, $matches[0]);echo "</br>---------------------剔除str1字串中非中文后----------------------</br>";echo "str1=&#39;".$str1."&#39;".":&emsp;字符长度:".mb_strlen($str1).":&emsp;字节长度:".strlen($str1)."&emsp;编码:".$encode1."</br>";echo "str1 与 str2比较:&emsp;";echo strcomp($str1,$str2)."</br>";function strcomp($str1,$str2){ 
  if($str1 == $str2){ 
    return "相等"; 
  }else{ 
    return "不等"; 
  } 
} 

?>

Running results

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Note:
Copy the 21-byte str1 to The sql input box of phpmyadmin displays as follows

Well, it’s just the two extra characters

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