Using regular expressions to extract Chinese implementation notes in PHP, _PHP tutorial

Using regular expressions to extract Chinese implementation notes in PHP,

Recently, my boss called me a small exercise in data duplication checking, which involves extracting and storing the Chinese fields from a file containing Chinese fields, and developing it using PHP. The middle involves the problem of Chinese matching of PHP regular expressions. I searched a lot on the Internet, but it was also very confusing and there was no accurate information. After modifying and testing my own code, I first wrote down the extract function.

The first thing to note is the encoding problem of double-byte characters. Here we may also encounter encoding problems such as Korean and Japanese in the future, which means the same thing as Chinese.

1. GBK (GB2312/GB18030)

Copy code The code is as follows:

x00-xff GBK double-byte encoding range
x20-x7f ASCII
xa1-xff Chinese gb2312
x80-xff Chinese gbk

2. UTF-8 (Unicode)

Copy code The code is as follows:

u4e00-u9fa5 (Chinese)
x3130-x318F (Korean
xAC00-xD7A3 (Korean)
u0800-u4e00 (Japanese)

Under Notepad++, we can first test whether our regular writing is wrong or not. I used [u4e00-u9fa5]+ to test the first expression. The + sign indicates more than one

matching character. The result is the same as expected. So, can this regular rule be used in scripts?

Let’s test it. We use preg_match_all('/[u4e00-u9fa5]+/', $subject,$matches) to call, and then you see this result: Compilation failed: PCRE does not support L, l, N{name}, U, or u at offset 2. . . . Isn’t it very big? ? What is the reason for this?

After consulting a lot of information, I found that u (PCRE_UTF8) is the PCRE above. This is a Perl library, including a perl-compatible regular expression library. This modifier enables an extra feature in PCRE that is incompatible with Perl. Pattern strings are treated as UTF-8. This modifier is available since PHP 4.1.0 under Unix and since PHP 4.2.3 under win32. PHP regular expressions also have different ways of expressing hexadecimal data. In PHP, x is used to represent hexadecimal data. Next, we will optimize the code and the detection function becomes:

Copy code The code is as follows:

class storeDataAdapter extends Store{
          private $dsData;                                                    /**
* Data conversion function, call preg_match_all to perform numerical matching based on $pattern regularity, and store the returned results in $matches in the form of an array,
* $matches[0] will contain text that matches the entire pattern, $matches[1] will contain text that matches the subpattern in the first captured bracket, and so on
* @see Store::data_convert()
                     */                                    Public function data_convert($pattern,$subject) {
                  $matches=array();                                          If (preg_match_all($pattern, $subject,$matches)){
                         return $matches[0];                                                                                                                                                                                                                                                 return null;                                                                                                                                                                                                               }  


When
is called, it becomes:




Copy code

The code is as follows:

$store=new storeDataAdapter($txtContent);

$match=array();

$dsName=$store->data_convert(‘/[x7f-xff]+/',$txtContent); foreach ($dsName as $val){ echo $val."
"; }  

The input file is:

, the following is the output file content after extracting Chinese:

, in line with expected needs.

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