is_countable

實例

檢查一個變量的內容是否是可計數的值：

 <span class="token php language-php"><span class="token delimiter important"><?php</span>
<span class="token variable">$a</span> <span class="token operator">=</span> <span class="token string double-quoted-string">"Hello"</span> <span class="token punctuation">;</span>
<span class="token keyword">echo</span> <span class="token string double-quoted-string">"a is "</span> <span class="token operator">.</span> <span class="token function">is_countable</span> <span class="token punctuation">(</span> <span class="token variable">$a</span> <span class="token punctuation">)</span> <span class="token operator">.</span> <span class="token string double-quoted-string">"<br>"</span> <span class="token punctuation">;</span>

<span class="token variable">$b</span> <span class="token operator">=</span> <span class="token keyword">array</span> <span class="token punctuation">(</span> <span class="token string double-quoted-string">"red"</span> <span class="token punctuation">,</span> <span class="token string double-quoted-string">"green"</span> <span class="token punctuation">,</span> <span class="token string double-quoted-string">"blue"</span> <span class="token punctuation">)</span> <span class="token punctuation">;</span>
<span class="token keyword">echo</span> <span class="token string double-quoted-string">"b is "</span> <span class="token operator">.</span> <span class="token function">is_countable</span> <span class="token punctuation">(</span> <span class="token variable">$b</span> <span class="token punctuation">)</span> <span class="token operator">.</span> <span class="token string double-quoted-string">"<br>"</span> <span class="token punctuation">;</span>

<span class="token variable">$c</span> <span class="token operator">=</span> <span class="token keyword">array</span> <span class="token punctuation">(</span> <span class="token string double-quoted-string">"Peter"</span> <span class="token operator">=></span> <span class="token string double-quoted-string">"35"</span> <span class="token punctuation">,</span> <span class="token string double-quoted-string">"Ben"</span> <span class="token operator">=></span> <span class="token string double-quoted-string">"37"</span> <span class="token punctuation">,</span> <span class="token string double-quoted-string">"Joe"</span> <span class="token operator">=></span> <span class="token string double-quoted-string">"43"</span> <span class="token punctuation">)</span> <span class="token punctuation">;</span>
<span class="token keyword">echo</span> <span class="token string double-quoted-string">"c is "</span> <span class="token operator">.</span> <span class="token function">is_countable</span> <span class="token punctuation">(</span> <span class="token variable">$c</span> <span class="token punctuation">)</span> <span class="token operator">.</span> <span class="token string double-quoted-string">"<br>"</span> <span class="token punctuation">;</span>

<span class="token variable">$d</span> <span class="token operator">=</span> <span class="token punctuation">[</span> <span class="token number">1</span> <span class="token punctuation">,</span> <span class="token number">2</span> <span class="token punctuation">,</span> <span class="token number">3</span> <span class="token punctuation">]</span> <span class="token punctuation">;</span>
<span class="token keyword">echo</span> <span class="token string double-quoted-string">"d is "</span> <span class="token operator">.</span> <span class="token function">is_countable</span> <span class="token punctuation">(</span> <span class="token variable">$d</span> <span class="token punctuation">)</span> <span class="token operator">.</span> <span class="token string double-quoted-string">"<br>"</span> <span class="token punctuation">;</span>
<span class="token delimiter important">?></span></span>

親自試一試

例子解釋：

變量$a包含一個字符串，它不是一個可計數的值，所以is_countable($a)將返回FALSE 。而變量$b 、 $c和$d包含的是數組，它們是可計數的值，所以is_countable($b) 、 is_countable($c)和is_countable($d)都將返回TRUE 。數組無論是索引數組還是關聯數組，都是可計數的。