Solution to the problem of Chinese garbled characters when php intercepts strings

In the previous article, we have given you the implementation of php interception String, and the use of php to intercept Chinese strings. Then when we intercept Chinese strings, many problems will occur. The problem of garbled characters, then today we will introduce to you how to solve the problem of Chinese garbled characters when intercepting strings in PHP!

PHP uses substr to intercept strings and the Chinese garbled problem occurs. Use mb_substr
Example:

mb_substr('截取中文乱码问题测试',0,5, 'utf-8');

Syntax:

string substr (string string, int start [, int length])
$rest = substr ("abcdef", 1); // returns "bcdef"
$rest = substr ("abcdef", 1, 3); // returns "bcd"

If start is a negative number, the returned string will It will start from the start character at the end of string.

$rest = substr ("abcdef", -1); // returns "f"
$rest = substr ("abcdef", -2); // returns "ef"
$rest = substr ("abcdef", -3, 1); // returns "d"

If the parameter length is given and is a positive number, the returned string will be length characters from start.

If the parameter length is given and is a negative number, the returned string will end at the length-th character from the end of string.

$rest = substr ("abcdef", 1, -1); // returns "bcde"

There is no problem with English. We test a Chinese

$rest = substr ("中国人", 1, -1); // returns "fdsafsda" 就是乱码了

The result of intercepting characters is definitely not the result we want. This appears PHP substr Chinese Garbled characters may cause the program to fail to run properly.
There are two main solutions

First, use mb_substr() of the mbstring extension library to intercept, so that garbled characters will not appear.
You can use the function mb_substr()/mb_strcut(). The usage of mb_substr()/mb_strcut() is similar to substr(), except that one more parameter needs to be added at the end of mb_substr()/mb_strcut to set String encoding,
But most servers do not open php_mbstring.dll. You need to open php_mbstring.dll in php.ini.

echo mb_substr("php中文字符encode",0,4,"utf-8");

If the last encoding parameter is not specified, three bytes will be one Chinese character. This is the characteristic of utf-8 encoding. If utf-8character set## is added #Explanation, therefore, it is intercepted in units of one word. When using, pay attention to the encoding of the php file and the encoding when displaying the web page. To use this mb_substr method, you need to know the encoding of the string in advance. If you don't know the encoding, you need to judge. The mbstring library also provides mb_check_encoding to check the string encoding, but it is not perfect yet.

string interception functions, among which substr and mb_substr are commonly used. When the former processes Chinese, GBK is 2 length units and UTF is 3 length units. After the latter specifies encoding, one Chinese character is 1 length unit.

picture, 5 Chinese characters are just right. If there are more than 5 characters, just intercept the first 4 and add "...". This way, there is no problem in processing Chinese characters, but when processing English or numbers, This interception would be too short.

2. Write the interception function yourself, but the efficiency is not as high as using the mbstring extension library. The following is a function in ecshop that intercepts strings encoded in UTF-8.

function sub_str($str, $length = , $append = true)
{
  $str = trim($str);
  $strlength = strlen($str);
  if ($length == || $length >= $strlength)
  {
    return $str; //截取长度等于或大于等于本字符串的长度，返回字符串本身
  }
  elseif ($length < ) //如果截取长度为负数
  {
    $length = $strlength + $length;//那么截取长度就等于字符串长度减去截取长度
    if ($length < )
    {
      $length = $strlength;//如果截取长度的绝对值大于字符串本身长度，则截取长度取字符串本身的长度
    }
  }
  if (function_exists(&#39;mb_substr&#39;))
  {
    $newstr = mb_substr($str, , $length, EC_CHARSET);
  }
  elseif (function_exists(&#39;iconv_substr&#39;))
  {
    $newstr = iconv_substr($str, , $length, EC_CHARSET);
  }
  else
  {
    //$newstr = trim_right(substr($str, , $length));
    $newstr = substr($str, , $length);
  }
  if ($append && $str != $newstr)
  {
    $newstr .= &#39;...&#39;;
  }
  return $newstr;
}

Summary:

Related recommendations:

Instances of intercepting Chinese strings and getting the number of characters in Chinese strings with php

Introduction to how to intercept strings with PHP

PHP interception Detailed explanation of usage of string function substr() function example

The above is the detailed content of Solution to the problem of Chinese garbled characters when php intercepts strings. For more information, please follow other related articles on the PHP Chinese website!