count_chars

实例

例子 1

返回一个字符串，包含所有在 "Hello World!" 中使用过的不同字符（模式 3）：

<span class="token php language-php"><span class="token delimiter important"><?php</span>
<span class="token variable">$str</span> <span class="token operator">=</span> <span class="token string double-quoted-string">"Hello World!"</span><span class="token punctuation">;</span>
<span class="token keyword">echo</span> <span class="token function">count_chars</span><span class="token punctuation">(</span><span class="token variable">$str</span><span class="token punctuation">,</span><span class="token number">3</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token delimiter important">?></span></span>

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例子 2

返回一个字符串，包含所有在 "Hello World!" 中未使用过的字符（模式 4）：

<span class="token php language-php"><span class="token delimiter important"><?php</span>
<span class="token variable">$str</span> <span class="token operator">=</span> <span class="token string double-quoted-string">"Hello World!"</span><span class="token punctuation">;</span>
<span class="token keyword">echo</span> <span class="token function">count_chars</span><span class="token punctuation">(</span><span class="token variable">$str</span><span class="token punctuation">,</span><span class="token number">4</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token delimiter important">?></span></span>

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例子 3

在此实例中，我们将使用 count_chars() 来检查字符串，返回模式设置为 1。模式 1 将返回一个数组，ASCII 值为键名，出现的次数为键值：

<span class="token php language-php"><span class="token delimiter important"><?php</span>
<span class="token variable">$str</span> <span class="token operator">=</span> <span class="token string double-quoted-string">"Hello World!"</span><span class="token punctuation">;</span>
<span class="token function">print_r</span><span class="token punctuation">(</span><span class="token function">count_chars</span><span class="token punctuation">(</span><span class="token variable">$str</span><span class="token punctuation">,</span><span class="token number">1</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token delimiter important">?></span></span>

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例子 4

统计某个 ASCII 字符在字符串中出现次数的另一个实例：

<span class="token php language-php"><span class="token delimiter important"><?php</span>
<span class="token variable">$str</span> <span class="token operator">=</span> <span class="token string double-quoted-string">"PHP is pretty fun!!"</span><span class="token punctuation">;</span>
<span class="token variable">$strArray</span> <span class="token operator">=</span> <span class="token function">count_chars</span><span class="token punctuation">(</span><span class="token variable">$str</span><span class="token punctuation">,</span><span class="token number">1</span><span class="token punctuation">)</span><span class="token punctuation">;</span>

<span class="token keyword">foreach</span> <span class="token punctuation">(</span><span class="token variable">$strArray</span> <span class="token keyword">as</span> <span class="token variable">$key</span><span class="token operator">=></span><span class="token variable">$value</span><span class="token punctuation">)</span>
  <span class="token punctuation">{</span>
<span class="token keyword">echo</span> <span class="token string double-quoted-string">"字符 <b>'"</span><span class="token operator">.</span><span class="token function">chr</span><span class="token punctuation">(</span><span class="token variable">$key</span><span class="token punctuation">)</span><span class="token operator">.</span><span class="token string double-quoted-string">"'</b> 被找到 <span class="token interpolation"><span class="token variable">$value</span></span> 次。<br>"</span><span class="token punctuation">;</span>
  <span class="token punctuation">}</span>
<span class="token delimiter important">?></span></span>

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