The simplest is to use
Example 1
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<? Php
Echo substr ("Hello world! ", 6 );
?> Output: World! Example 2
<? Php
Echo substr ("Hello world! ", 6, 5 );
?> |
There is no problem in English, but there is a problem in Chinese. Next we will use the mb_substr function for processing.
/**
*--------------------------------------
* PHP has an mbstring extension library that can be used (I was asked this question when I interviewed PHP), *
Php_mbstring.dll is not enabled on normal servers.
* Open php_mbstring.dll in php. ini. If you do not have the permission, contact your ISP.
* Because mb_string is more efficient, check whether mb_string can be used:
*--------------------------------------
*/
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If (function_exists ('MB _ string '))
{
Mb_substr ($ string, $ start, $ length, $ encoding );
// Other codes here
}
Else mysubstr ($ string, $ start, $ length); // call your own function
?> |
First define your own functions
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<? Php
/**
*------------
* First define your own functions:
*------------
*/
Function mysubstr ($ string, $ start, $ length)
{
If (strlen ($ string)> $ length)
{
$ Str = ";
$ Len = $ start + $ length;
For ($ I = $ start; $ I <$ len; $ I ++)
{
If (ord (substr ($ string, $ I, 1)> 0xa0)
{
$ Str. = substr ($ string, $ I, 2 );
$ I ++;
}
Else {$ str. = substr ($ string, $ I, 1 );}
}
Return $ str .'... ';
}
Else {return $ string ;}
} |
Note that when using this method, the charset in your
The following is a common Chinese/English character truncation function.
The custom function to intercept Chinese strings is basically to write a function like mb_substr and call it directly. The code I found below is actually very simple.
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<? Php
Function substr_cn ($ string_input, $ start, $ length)
{
/* Function:
* This algorithm is used to intercept Chinese strings.
* The function is truncated in units of a single complete character. That is, one English character and one Chinese character both represent a unit length.
* Parameters:
* The $ string parameter is the string to be truncated,
* The $ start parameter indicates the starting position of the part to be intercepted,
* The $ length parameter indicates the number of characters to be intercepted (one Chinese character or one English character)
* Return value:
* Returns the truncated result string.
**/
$ Str_input = $ string_input;
$ Len = $ length;
$ Return_str = "";
// Define an empty string
For ($ I = 0; $ I <2 * $ len + 2; $ I ++)
$ Return_str = $ return_str ."";
$ Start_index = 0;
// Calculate the start byte offset
For ($ I = 0; $ I <$ start; $ I ++)
{
If (ord ($ str_input {$ start_index}> = 161) // It is a Chinese character.
{
$ Start_index + = 2;
}
Else // English
{
$ Start_index + = 1;
}
}
$ Chr_index = $ start_index;
// Capture
For ($ I = 0; $ I <$ len; $ I ++)
{
$ Asc = ord ($ str_input {$ chr_index });
If ($ asc> = 161)
{
$ Return_str {$ I} = chr ($ asc );
$ Return_str {$ I + 1} = chr (ord ($ str_input {$ chr_index + 1 }));
$ Len + = 1; // add 1 to the end condition
$ I ++; // The position Offset Plus 1
$ Chr_index + = 2;
Continue;
}
Else
{
$ Return_str {$ I} = chr ($ asc );
$ Chr_index + = 1;
}
}
Return trim ($ return_str );
} // End of substr_cn
?> |
