Question mark intercepted by Chinese character strings in php

The time for php to operate on strings is nothing more than two problems:
1. Determine whether the string encoding is gbk or unicode.
2. Extract the corresponding encoding.

In general, we may encounter garbled characters when using substr to intercept Chinese characters. Because the Chinese character is dubyte, when a byte is intercepted, the Chinese character cannot be displayed and is out of order.

In fact, the solution is very simple. See the following screenshot function:

The code is as follows:	Copy code
// Truncate an extra long string Function curtStr ($ str, $ len = 30 ){ If (strlen ($ str)> $ len ){ $ Str = substr ($ str, 0, $ len ); $ Str. = chr (0 )."... "; Return $ str; }

The above chr (0) is not null
Null is nothing, while chr (0) is 0. The hexadecimal value is 0 × 00, and the binary value is 00000000.
Although chr (0) does not display anything, it is a character.
When a Chinese character is truncated, according to the encoding rules, he always needs to pull the other characters behind it as an explanation of the Chinese character. This is the cause of garbled characters. The combination of 0x81 to 0xff and 0x00 is always displayed as "null"
Based on this feature, add a chr (0) after the substr result to prevent garbled characters.

The following are some functions that can be used to precisely intercept Chinese strings:

Truncates UTF-8 encoded multi-byte strings.

The code is as follows:	Copy code
<? Php // Truncate the utf8 string Function utf8Substr ($ str, $ from, $ len)    {   Return preg_replace ('# ^ (? : [X00-x7F] | [xC0-xFF] [x80-xBF] +) {0, '. $ from .'}'. '((? : [X00-x7F] | [xC0-xFF] [x80-xBF] +) {0, '. $ len.'}). * # s ', '$ 1', $ str );    }   ?>

Chinese character truncation functions supported by UTF-8 and GB2312

The code is as follows:

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<? Php /* Chinese character truncation functions supported by Utf-8 and gb2312 Cut_str (string, truncation length, start length, encoding ); The default encoding format is UTF-8. The default start length is 0. */   Function cut_str ($ string, $ sublen, $ start = 0, $ code = 'utf-8 ')    {    If ($ code = 'utf-8 ')       {    $ Pa = "/[x01-x7f] | [xc2-xdf] [x80-xbf] | xe0 [xa0-xbf] [x80-xbf] | [xe1-xef] [x80-xbf] [x80-xbf] | xf0 [x90-xbf] [x80-xbf]] [x80-xbf] | [xf1-xf7] [x80-xbf] [x80-xbf] [x80-xbf]/"; Preg_match_all ($ pa, $ string, $ t_string );   If (count ($ t_string [0])-$ start> $ sublen) return join ('', array_slice ($ t_string [0], $ start, $ sublen )). "... "; Return join ('', array_slice ($ t_string [0], $ start, $ sublen ));       }    Else       {    $ Start = $ start * 2; $ Sublen = $ sublen * 2; $ Strlen = strlen ($ string ); $ Tmpstr = '';   For ($ I = 0; $ I <$ strlen; $ I ++)           {    If ($ I >=$ start & $ I <($ start + $ sublen ))               {    If (ord (substr ($ string, $ I, 1)> 129)                   {    $ Tmpstr. = substr ($ string, $ I, 2 );                   }    Else                   {    $ Tmpstr. = substr ($ string, $ I, 1 );                   }                  }    If (ord (substr ($ string, $ I, 1)> 129) $ I ++;           }    If (strlen ($ tmpstr) <$ strlen) $ tmpstr. = "..."; Return $ tmpstr;       }       }      $ Str = "the string to be intercepted by abcd "; Echo cut_str ($ str, 8, 0, 'gb2312 '); ?>