How to implement Chinese string interception in php

In PHP, you can use the mb_substr() function to intercept a Chinese string. This function can intercept a specified part of a string. It is not only valid for English characters, but also for Chinese characters; the syntax format is " mb_substr($str,$start,$length,$encoding)".

The operating environment of this tutorial: windows7 system, PHP7.1 version, DELL G3 computer

mb_substr() function can select from a string Intercept the specified part. Different from the substr() function, the mb_substr() function is not only valid for English characters, but also for Chinese characters. Its syntax format is as follows:

mb_substr($str , $start [, $length = NULL [, $encoding = mb_internal_encoding()]])

The parameter description is as follows:

• $str: The string to be intercepted, the string contains at least one character;
• $start: The starting position of the intercepted string;
  • If $start is not If $start is a negative number, the string will be intercepted from the $start character of $str;
  • If $start is a negative number, the string will be intercepted from the end of $str to the $start character. Start intercepting the location.
• $length: Optional parameter, indicating the length of the intercepted string;
  • If $length is a positive number, the string will be intercepted backwards from the $start position Up to $length characters;
  • If $length is a negative number, then $length characters at the end of $string will be omitted (if $start is a negative number, it will be counted from the end of the string);
  • If the value of $length is NULL or $length is omitted, it will be cut to the end of the string.
• $encoding: Optional parameter, indicating the character encoding of $str. If omitted, the internal character encoding is used.

[Example] Use the mb_substr() function to intercept a Chinese string of specified length.

<?php
    $str = &#39;欢迎访问PHP中文网，一个在线学习编程的网站。&#39;;
    echo mb_substr($str, 4).&#39;<br>&#39;;
    echo mb_substr($str, -19).&#39;<br>&#39;;
    echo mb_substr($str, 4, 6).&#39;<br>&#39;;
    echo mb_substr($str, 4, -16).&#39;<br>&#39;;
    echo mb_substr($str, -19, -13).&#39;<br>&#39;;
    echo mb_substr($str, -19, 6).&#39;<br>&#39;;
    var_dump(mb_substr($str, 40));
    echo &#39;<br>&#39;;
    var_dump(mb_substr($str, 4, null));
?>

The running results are as follows:

PHP中文网，一个在线学习编程的网站。
PHP中文网，一个在线学习编程的网站。
PHP中文网
PHP
PHP中文网
PHP中文网
string(0) ""
string(55) "PHP中文网，一个在线学习编程的网站。"

[Example] Use the mb_substr() function to intercept a string of specified length, and replace the excess part with "...".

<?php
    $str = &#39;PHP中文网是一个在线学习编程的网站，我们发布了多套文字教程，它们都通俗易懂，深入浅出。&#39;;
    if(strlen($str)>18){
        echo mb_substr($str, 0, 18).&#39;...&#39;;
    }else{
        echo $str;
    }
?>

The running results are as follows:

PHP中文网是一个在线学习编程的网站...

Recommended learning: "PHP Video Tutorial"

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