preg_replace_callback

名称:preg_replace_callback

分类:正则处理PCRE

所属语言:php

一句话介绍:给定表达式和回调，返回字符串，其中表达式的所有匹配项都被替换为回调函数返回的子字符串。

实例

计算句子中所有单词的字母数：

<span class="token php language-php"><span class="token delimiter important"><?php</span>
<span class="token keyword">function</span> <span class="token function-definition function">countLetters</span><span class="token punctuation">(</span><span class="token variable">$matches</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
  <span class="token keyword">return</span> <span class="token variable">$matches</span><span class="token punctuation">[</span><span class="token number">0</span><span class="token punctuation">]</span> <span class="token operator">.</span> <span class="token string single-quoted-string">'('</span> <span class="token operator">.</span> <span class="token function">strlen</span><span class="token punctuation">(</span><span class="token variable">$matches</span><span class="token punctuation">[</span><span class="token number">0</span><span class="token punctuation">]</span><span class="token punctuation">)</span> <span class="token operator">.</span> <span class="token string single-quoted-string">')'</span><span class="token punctuation">;</span>
<span class="token punctuation">}</span>

<span class="token variable">$input</span> <span class="token operator">=</span> <span class="token string double-quoted-string">"Welcome to W3School.com.cn!"</span><span class="token punctuation">;</span>
<span class="token variable">$pattern</span> <span class="token operator">=</span> <span class="token string single-quoted-string">'/[a-z0-9\.]+/i'</span><span class="token punctuation">;</span>
<span class="token variable">$result</span> <span class="token operator">=</span> <span class="token function">preg_replace_callback</span><span class="token punctuation">(</span><span class="token variable">$pattern</span><span class="token punctuation">,</span> <span class="token string single-quoted-string">'countLetters'</span><span class="token punctuation">,</span> <span class="token variable">$input</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token keyword">echo</span> <span class="token variable">$result</span><span class="token punctuation">;</span>
<span class="token delimiter important">?></span></span>

亲自试一试