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array_map

為數組的每個元素應用回調函數
名稱:array_map
分類:數組
所屬語言:php
一句話介紹:把數組中的每個值發送到用戶自定義函數,返回新的值。

實例

例子1

將函數作用到數組中的每個值上,每個值都乘以本身,並返回帶有新值的數組:

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

親自試一試

例子2

使用用戶自定義函數來改變數組的值:

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

親自試一試

例子3

使用兩個數組:

 <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></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>

親自試一試

例子4

將數組中值的所有字母改為大寫:

 <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>

親自試一試

例子5

將函數名賦值為null 時:

 <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></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>

親自試一試

同類函數
  • 使用鍵名比較計算數組的差集 array_diff_key

    array_diff_key

    使用鍵名比較計算數組的差集
  • 使用鍵名比較計算數組的交集 array_intersect_key

    array_intersect_key

    使用鍵名比較計算數組的交集
  • 用回調函數比較數據來計算數組的差集 array_udiff

    array_udiff

    用回調函數比較數據來計算數組的差集
  • 檢查給定的數組是否是一個列表 array_is_list

    array_is_list

    檢查給定的數組是否是一個列表
  • 打亂數組 shuffle

    shuffle

    打亂數組
  • 對數組排序 sort

    sort

    對數組排序
  • 交換數組中的鍵和值 array_flip

    array_flip

    交換數組中的鍵和值
  • 使用指定的鍵和值填充數組 array_fill_keys

    array_fill_keys

    使用指定的鍵和值填充數組
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