Problem analysis of PHP mb_strwidth in actual use_PHP tutorial-PHP Tutorial-php.cn

Problem analysis of PHP mb_strwidth in actual use_PHP tutorial

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Release： 2016-07-15 13:30:39

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The news part of a recent PHP website project needs a function to intercept the string according to the width of the title and add "..." at the end. The first thing that comes to mind is to use PHP's mb _String function implementation, mb_strimwidth, mb_strwidth, and later found that if there is a "" symbol in the title, PHP mb_strwidth will consider the symbol to be 1 width. I wonder if this is not a Chinese double quotation mark. Logically speaking, it must be wide Bytes, the length should be 2 widths, and then query "" unicode is u201C and u201D respectively, which are not in the range of Chinese characters. Then query the code table of unicode.org and find that u2000-u206F is the range of universal symbols. This range Although the characters in are all in the form of wide characters, PHP's mb_ function considers them to be 1 width. We have no choice but to rely on ourselves.

The following are the functions implemented:

<ol class="dp-xml">
<li class="alt"><span><span>function truncString($str, $length)  </span></span></li>
<li><span>{  </span></li>
<li class="alt">
<span>$</span><span class="attribute">countLen</span><span>=</span><span class="attribute-value">0</span><span>;  </span>
</li>
<li>
<span>for($</span><span class="attribute">i</span><span>=</span><span class="attribute-value">0</span><span>;$i</span><span class="tag"><</span><span class="tag-name">mb_strlen</span><span>($str);$i++)  </span></li><li class="alt"><span>{  </span></li><li><span>$countLen+=amb_strwidth(mb_substr($str,$i,1));  </span></li><li class="alt"><span>if($countLen</span><span class="tag">></span><span>$length)  </span>
</li>
<li><span>return mb_substr($str,0,$i);  </span></li>
<li class="alt"><span>}  </span></li>
<li><span>return $str;  </span></li>
<li class="alt"><span>}  </span></li>
<li><span>function amb_strwidth($str_width)  </span></li>
<li class="alt"><span>{  </span></li>
<li>
<span>$</span><span class="attribute">count</span><span>=</span><span class="attribute-value">0</span><span>;  </span>
</li>
<li class="alt">
<span>for($</span><span class="attribute">i</span><span>=</span><span class="attribute-value">0</span><span>;$i</span><span class="tag"><</span><span class="tag-name">mb_strlen</span><span>($str_width);$i++)  </span>
</li>
<li><span>{  </span></li>
<li class="alt"><span>//if(mb_substr($str_width,$i,1)=="xE2x80x9C"||mb_substr($str_width,$i,1)=='xE2x80x9D')  </span></li>
<li><span>//如果遇到u2000-u206F内的字符则将计数器加2  </span></li>
<li class="alt"><span>if(preg_match("/[x{2000}-x{206F}]/u",mb_substr($str_width,$i,1)))  </span></li>
<li><span>$count+=2;  </span></li>
<li class="alt"><span>else  </span></li>
<li><span>$count+=mb_strwidth(mb_substr($str_width,$i,1));  </span></li>
<li class="alt"><span>}  </span></li>
<li><span>return $count;  </span></li>
<li class="alt"><span>} </span></li>
</ol>

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The above are the specific solutions to problems when using PHP mb_strwidth. I hope it will be helpful to everyone. .