array_map

实例

例子 1

将函数作用到数组中的每个值上，每个值都乘以本身，并返回带有新值的数组：

<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">myfunction</span><span class="token punctuation">(</span><span class="token variable">$v</span><span class="token punctuation">)</span>
<span class="token punctuation">{</span>
  <span class="token keyword">return</span><span class="token punctuation">(</span><span class="token variable">$v</span><span class="token operator">*</span><span class="token variable">$v</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">}</span>

<span class="token variable">$a</span><span class="token operator">=</span><span class="token keyword">array</span><span class="token punctuation">(</span><span class="token number">1</span><span class="token punctuation">,</span><span class="token number">2</span><span class="token punctuation">,</span><span class="token number">3</span><span class="token punctuation">,</span><span class="token number">4</span><span class="token punctuation">,</span><span class="token number">5</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token function">print_r</span><span class="token punctuation">(</span><span class="token function"></span><mark><span class="token function">array_map</span><span class="token punctuation">(</span><span class="token string double-quoted-string">"myfunction"</span><span class="token punctuation">,</span><span class="token variable">$a</span><span class="token punctuation">)</span></mark><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 2

使用用户自定义函数来改变数组的值：

<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">myfunction</span><span class="token punctuation">(</span><span class="token variable">$v</span><span class="token punctuation">)</span>
<span class="token punctuation">{</span>
<span class="token keyword">if</span> <span class="token punctuation">(</span><span class="token variable">$v</span><span class="token operator">===</span><span class="token string double-quoted-string">"Dog"</span><span class="token punctuation">)</span>
  <span class="token punctuation">{</span>
  <span class="token keyword">return</span> <span class="token string double-quoted-string">"Fido"</span><span class="token punctuation">;</span>
  <span class="token punctuation">}</span>
<span class="token keyword">return</span> <span class="token variable">$v</span><span class="token punctuation">;</span>
<span class="token punctuation">}</span>

<span class="token variable">$a</span><span class="token operator">=</span><span class="token keyword">array</span><span class="token punctuation">(</span><span class="token string double-quoted-string">"Horse"</span><span class="token punctuation">,</span><span class="token string double-quoted-string">"Dog"</span><span class="token punctuation">,</span><span class="token string double-quoted-string">"Cat"</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token function">print_r</span><span class="token punctuation">(</span><span class="token function"></span><mark><span class="token function">array_map</span><span class="token punctuation">(</span><span class="token string double-quoted-string">"myfunction"</span><span class="token punctuation">,</span><span class="token variable">$a</span><span class="token punctuation">)</span></mark><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 3

使用两个数组：

<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">myfunction</span><span class="token punctuation">(</span><span class="token variable">$v1</span><span class="token punctuation">,</span><span class="token variable">$v2</span><span class="token punctuation">)</span>
<span class="token punctuation">{</span>
<span class="token keyword">if</span> <span class="token punctuation">(</span><span class="token variable">$v1</span><span class="token operator">===</span><span class="token variable">$v2</span><span class="token punctuation">)</span>
  <span class="token punctuation">{</span>
  <span class="token keyword">return</span> <span class="token string double-quoted-string">"same"</span><span class="token punctuation">;</span>
  <span class="token punctuation">}</span>
<span class="token keyword">return</span> <span class="token string double-quoted-string">"different"</span><span class="token punctuation">;</span>
<span class="token punctuation">}</span>

<span class="token variable">$a1</span><span class="token operator">=</span><span class="token keyword">array</span><span class="token punctuation">(</span><span class="token string double-quoted-string">"Horse"</span><span class="token punctuation">,</span><span class="token string double-quoted-string">"Dog"</span><span class="token punctuation">,</span><span class="token string double-quoted-string">"Cat"</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token variable">$a2</span><span class="token operator">=</span><span class="token keyword">array</span><span class="token punctuation">(</span><span class="token string double-quoted-string">"Cow"</span><span class="token punctuation">,</span><span class="token string double-quoted-string">"Dog"</span><span class="token punctuation">,</span><span class="token string double-quoted-string">"Rat"</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token function">print_r</span><span class="token punctuation">(</span><span class="token function"></span><mark><span class="token function">array_map</span><span class="token punctuation">(</span><span class="token string double-quoted-string">"myfunction"</span><span class="token punctuation">,</span><span class="token variable">$a1</span><span class="token punctuation">,</span><span class="token variable">$a2</span><span class="token punctuation">)</span></mark><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

将数组中值的所有字母改为大写：

<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">myfunction</span><span class="token punctuation">(</span><span class="token variable">$v</span><span class="token punctuation">)</span>
<span class="token punctuation">{</span>
<span class="token variable">$v</span><span class="token operator">=</span><span class="token function">strtoupper</span><span class="token punctuation">(</span><span class="token variable">$v</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
  <span class="token keyword">return</span> <span class="token variable">$v</span><span class="token punctuation">;</span>
<span class="token punctuation">}</span>

<span class="token variable">$a</span><span class="token operator">=</span><span class="token keyword">array</span><span class="token punctuation">(</span><span class="token string double-quoted-string">"Animal"</span> <span class="token operator">=></span> <span class="token string double-quoted-string">"horse"</span><span class="token punctuation">,</span> <span class="token string double-quoted-string">"Type"</span> <span class="token operator">=></span> <span class="token string double-quoted-string">"mammal"</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token function">print_r</span><span class="token punctuation">(</span><span class="token function">array_map</span><span class="token punctuation">(</span><span class="token string double-quoted-string">"myfunction"</span><span class="token punctuation">,</span><span class="token variable">$a</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 5

将函数名赋值为 null 时：

<span class="token php language-php"><span class="token delimiter important"><?php</span>
<span class="token variable">$a1</span><span class="token operator">=</span><span class="token keyword">array</span><span class="token punctuation">(</span><span class="token string double-quoted-string">"Dog"</span><span class="token punctuation">,</span><span class="token string double-quoted-string">"Cat"</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token variable">$a2</span><span class="token operator">=</span><span class="token keyword">array</span><span class="token punctuation">(</span><span class="token string double-quoted-string">"Puppy"</span><span class="token punctuation">,</span><span class="token string double-quoted-string">"Kitten"</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token function">print_r</span><span class="token punctuation">(</span><span class="token function"></span><mark><span class="token function">array_map</span><span class="token punctuation">(</span><span class="token constant">null</span><span class="token punctuation">,</span><span class="token variable">$a1</span><span class="token punctuation">,</span><span class="token variable">$a2</span><span class="token punctuation">)</span></mark><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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