PHP program code to determine whether a string encoding is utf-8

PHP program code to determine whether a string encoding is utf-8_PHP tutorial

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Release： 2016-07-13 10:48:50

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This article will introduce to you the program code for PHP to determine whether the string encoding is utf-8. If you are interested, feel free to enter it for reference.

We used to use mb_detect_encoding() to detect character encoding

代码如下	复制代码
//判断字符串是什么编码 if ($tag === mb_convert_encoding(mb_convert_encoding($tag, "GB2312", "UTF-8"), "UTF-8", "GB2312")) { } else {//如果是gb2312 的就转换为utf8的 $tag = mb_convert_encoding($tag, 'UTF-8', 'GB2312'); }

$keytitle = “%D0%BE%C6%AC”; The detection result is UTF-8. This bug is not actually a bug, and you should not rely too much on mb_detect_encoding when writing programs. When the string is short, the detection results are likely to be biased.
How to solve it? My solution is:

Adjust the order of encoding detection to put the greatest possibility first, thus reducing the chance of incorrect conversion.

The code is as follows

代码如下	复制代码
$encode = mb_detect_encoding($keytitle, array('ASCII','GB2312′,'GBK','UTF-8');

Copy code

$encode = mb_detect_encoding($keytitle, array('ASCII','GB2312′,'GBK','UTF-8');

The

代码如下

复制代码

// Returns true if $string is valid UTF-8 and false otherwise.
function is_utf8($word)
{
if (preg_match("/^([".chr(228)."-".chr(233)."]{1}[".chr(128)."-".chr(191)."]{1}[".chr(128)."-".chr(191)."]{1}){1}/",$word) == true || preg_match("/([".chr(228)."-".chr(233)."]{1}[".chr(128)."-".chr(191)."]{1}[".chr(128)."-".chr(191)."]{1}){1}$/",$word) == true || preg_match("/([".chr(228)."-".chr(233)."]{1}[".chr(128)."-".chr(191)."]{1}[".chr(128)."-".chr(191)."]{1}){2,}/",$word) == true)
{
return true;
}
else
{
return false;
}
} // function is_utf8

parameters are: the input variable to be detected, the detection order of the encoding method (once it is true, it will be automatically ignored later), and the strict mode

The above method still can’t solve it, so I found another solution below.

Example 1