study/uTools-Manuals
1
0
Fork 0
mirror of https://github.com/fofolee/uTools-Manuals.git synced 2025-06-17 21:16:57 +08:00
Code Issues Packages Projects Releases Wiki Activity
uTools-Manuals/docs/php/array_map.html
fofolee 7ca94f1141 0.0.1
2019-04-08 23:22:26 +08:00

322 lines
19 KiB
HTML
Raw Blame History

This file contains ambiguous Unicode characters

This file contains Unicode characters that might be confused with other characters. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<title>为数组的每个元素应用回调函数</title>
</head>
<body class="docs"><div id="layout">
<div id="layout-content"><div id="function.array-map" class="refentry">
<div class="refnamediv">
<h1 class="refname">array_map</h1>
<p class="verinfo">(PHP 4 &gt;= 4.0.6, PHP 5, PHP 7)</p><p class="refpurpose"><span class="refname">array_map</span> &mdash; <span class="dc-title">
为数组的每个元素应用回调函数
</span></p>
</div>
<div class="refsect1 description" id="refsect1-function.array-map-description">
<h3 class="title">说明</h3>
<div class="methodsynopsis dc-description">
<span class="methodname"><strong>array_map</strong></span>
( <span class="methodparam"><span class="type"><a href="language.types.callable.html" class="type callable">callable</a></span> <code class="parameter">$callback</code></span>
, <span class="methodparam"><span class="type">array</span> <code class="parameter">$array1</code></span>
[, <span class="methodparam"><span class="type">array</span> <code class="parameter">$...</code></span>
] ) : <span class="type">array</span></div>
<p class="para rdfs-comment">
<span class="function"><strong>array_map()</strong></span>：返回数组，是为 <code class="parameter">array1</code> 每个元素应用 <code class="parameter">callback</code>函数之后的数组。
<code class="parameter">callback</code> 函数形参的数量和传给 <span class="function"><strong>array_map()</strong></span> 数组数量，两者必须一样。
</p>
</div>
<div class="refsect1 parameters" id="refsect1-function.array-map-parameters">
<h3 class="title">参数</h3>
<p class="para">
<dl>
<dt>
<code class="parameter">callback</code></dt>
<dd>
<p class="para">
回调函数，应用到每个数组里的每个元素。
</p>
</dd>
<dt>
<code class="parameter">array1</code></dt>
<dd>
<p class="para">
数组，遍历运行 <code class="parameter">callback</code> 函数。
</p>
</dd>
<dt>
<code class="parameter">...</code></dt>
<dd>
<p class="para">
数组列表，每个都遍历运行 <code class="parameter">callback</code> 函数。
</p>
</dd>
</dl>
</p>
</div>
<div class="refsect1 returnvalues" id="refsect1-function.array-map-returnvalues">
<h3 class="title">返回值</h3>
<p class="para">
返回数组，包含 <code class="parameter">callback</code> 函数处理之后 <code class="parameter">array1</code> 的所有元素。
</p>
</div>
<div class="refsect1 examples" id="refsect1-function.array-map-examples">
<h3 class="title">范例</h3>
<p class="para">
<div class="example" id="example-6041">
<p><strong>Example #1 <span class="function"><strong>array_map()</strong></span> 例子</strong></p>
<div class="example-contents">
<div class="phpcode"><pre><span style="color: #000000">
<span style="color: #0000BB">&lt;?php<br /></span><span style="color: #007700">function&nbsp;</span><span style="color: #0000BB">cube</span><span style="color: #007700">(</span><span style="color: #0000BB">$n</span><span style="color: #007700">)<br />{<br />&nbsp;&nbsp;&nbsp;&nbsp;return(</span><span style="color: #0000BB">$n&nbsp;</span><span style="color: #007700">*&nbsp;</span><span style="color: #0000BB">$n&nbsp;</span><span style="color: #007700">*&nbsp;</span><span style="color: #0000BB">$n</span><span style="color: #007700">);<br />}<br /><br /></span><span style="color: #0000BB">$a&nbsp;</span><span style="color: #007700">=&nbsp;array(</span><span style="color: #0000BB">1</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">2</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">3</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">4</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">5</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">$b&nbsp;</span><span style="color: #007700">=&nbsp;</span><span style="color: #0000BB">array_map</span><span style="color: #007700">(</span><span style="color: #DD0000">"cube"</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">$a</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">print_r</span><span style="color: #007700">(</span><span style="color: #0000BB">$b</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">?&gt;</span>
</span>
</pre></div>
</div>
<div class="example-contents"><p>
这使得 <var class="varname"><var class="varname">$b</var></var> 成为：
</p></div>
<div class="example-contents screen">
<div class="cdata"><pre>
Array
(
[0] =&gt; 1
[1] =&gt; 8
[2] =&gt; 27
[3] =&gt; 64
[4] =&gt; 125
)
</pre></div>
</div>
</div>
</p>
<p class="para">
<div class="example" id="example-6042">
<p><strong>Example #2 <span class="function"><strong>array_map()</strong></span> 使用匿名函数 (PHP 5.3.0 起)</strong></p>
<div class="example-contents">
<div class="phpcode"><pre><span style="color: #000000">
<span style="color: #0000BB">&lt;?php<br />$func&nbsp;</span><span style="color: #007700">=&nbsp;function(</span><span style="color: #0000BB">$value</span><span style="color: #007700">)&nbsp;{<br />&nbsp;&nbsp;&nbsp;&nbsp;return&nbsp;</span><span style="color: #0000BB">$value&nbsp;</span><span style="color: #007700">*&nbsp;</span><span style="color: #0000BB">2</span><span style="color: #007700">;<br />};<br /><br /></span><span style="color: #0000BB">print_r</span><span style="color: #007700">(</span><span style="color: #0000BB">array_map</span><span style="color: #007700">(</span><span style="color: #0000BB">$func</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">range</span><span style="color: #007700">(</span><span style="color: #0000BB">1</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">5</span><span style="color: #007700">)));<br /></span><span style="color: #0000BB">?&gt;</span>
</span>
</pre></div>
</div>
<div class="example-contents screen">
<div class="cdata"><pre>
Array
(
[0] =&gt; 2
[1] =&gt; 4
[2] =&gt; 6
[3] =&gt; 8
[4] =&gt; 10
)
</pre></div>
</div>
</div>
</p>
<p class="para">
<div class="example" id="example-6043">
<p><strong>Example #3 <span class="function"><strong>array_map()</strong></span>：使用更多的数组</strong></p>
<div class="example-contents">
<div class="phpcode"><pre><span style="color: #000000">
<span style="color: #0000BB">&lt;?php<br /></span><span style="color: #007700">function&nbsp;</span><span style="color: #0000BB">show_Spanish</span><span style="color: #007700">(</span><span style="color: #0000BB">$n</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">$m</span><span style="color: #007700">)<br />{<br />&nbsp;&nbsp;&nbsp;&nbsp;return(</span><span style="color: #DD0000">"The&nbsp;number&nbsp;</span><span style="color: #0000BB">$n</span><span style="color: #DD0000">&nbsp;is&nbsp;called&nbsp;</span><span style="color: #0000BB">$m</span><span style="color: #DD0000">&nbsp;in&nbsp;Spanish"</span><span style="color: #007700">);<br />}<br /><br />function&nbsp;</span><span style="color: #0000BB">map_Spanish</span><span style="color: #007700">(</span><span style="color: #0000BB">$n</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">$m</span><span style="color: #007700">)<br />{<br />&nbsp;&nbsp;&nbsp;&nbsp;return(array(</span><span style="color: #0000BB">$n&nbsp;</span><span style="color: #007700">=&gt;&nbsp;</span><span style="color: #0000BB">$m</span><span style="color: #007700">));<br />}<br /><br /></span><span style="color: #0000BB">$a&nbsp;</span><span style="color: #007700">=&nbsp;array(</span><span style="color: #0000BB">1</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">2</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">3</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">4</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">5</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">$b&nbsp;</span><span style="color: #007700">=&nbsp;array(</span><span style="color: #DD0000">"uno"</span><span style="color: #007700">,&nbsp;</span><span style="color: #DD0000">"dos"</span><span style="color: #007700">,&nbsp;</span><span style="color: #DD0000">"tres"</span><span style="color: #007700">,&nbsp;</span><span style="color: #DD0000">"cuatro"</span><span style="color: #007700">,&nbsp;</span><span style="color: #DD0000">"cinco"</span><span style="color: #007700">);<br /><br /></span><span style="color: #0000BB">$c&nbsp;</span><span style="color: #007700">=&nbsp;</span><span style="color: #0000BB">array_map</span><span style="color: #007700">(</span><span style="color: #DD0000">"show_Spanish"</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">$a</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">$b</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">print_r</span><span style="color: #007700">(</span><span style="color: #0000BB">$c</span><span style="color: #007700">);<br /><br /></span><span style="color: #0000BB">$d&nbsp;</span><span style="color: #007700">=&nbsp;</span><span style="color: #0000BB">array_map</span><span style="color: #007700">(</span><span style="color: #DD0000">"map_Spanish"</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">$a&nbsp;</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">$b</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">print_r</span><span style="color: #007700">(</span><span style="color: #0000BB">$d</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">?&gt;</span>
</span>
</pre></div>
</div>
<div class="example-contents"><p>以上例程会输出：</p></div>
<div class="example-contents screen">
<div class="cdata"><pre>
// printout of $c
Array
(
[0] =&gt; The number 1 is called uno in Spanish
[1] =&gt; The number 2 is called dos in Spanish
[2] =&gt; The number 3 is called tres in Spanish
[3] =&gt; The number 4 is called cuatro in Spanish
[4] =&gt; The number 5 is called cinco in Spanish
)
// printout of $d
Array
(
[0] =&gt; Array
(
[1] =&gt; uno
)
[1] =&gt; Array
(
[2] =&gt; dos
)
[2] =&gt; Array
(
[3] =&gt; tres
)
[3] =&gt; Array
(
[4] =&gt; cuatro
)
[4] =&gt; Array
(
[5] =&gt; cinco
)
)
</pre></div>
</div>
</div>
</p>
<p class="para">
传入两个及以上的数组时，它们元素数量将会相同。因为回调函数会并行地处理相互对应的元素。
如果几个数组的元素数量不一致：空元素会扩展短那个数组，直到长度和最长的数组一样。
</p>
<p class="para">
此函数有个有趣的用法：传入 <strong><code>NULL</code></strong> 作为回调函数的名称，将创建多维数组（一个数组，内部包含数组。）
</p>
<p class="para">
<div class="example" id="example-6044">
<p><strong>Example #4 多维数组：创建数组，内部包含数组</strong></p>
<div class="example-contents">
<div class="phpcode"><pre><span style="color: #000000">
<span style="color: #0000BB">&lt;?php<br />$a&nbsp;</span><span style="color: #007700">=&nbsp;array(</span><span style="color: #0000BB">1</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">2</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">3</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">4</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">5</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">$b&nbsp;</span><span style="color: #007700">=&nbsp;array(</span><span style="color: #DD0000">"one"</span><span style="color: #007700">,&nbsp;</span><span style="color: #DD0000">"two"</span><span style="color: #007700">,&nbsp;</span><span style="color: #DD0000">"three"</span><span style="color: #007700">,&nbsp;</span><span style="color: #DD0000">"four"</span><span style="color: #007700">,&nbsp;</span><span style="color: #DD0000">"five"</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">$c&nbsp;</span><span style="color: #007700">=&nbsp;array(</span><span style="color: #DD0000">"uno"</span><span style="color: #007700">,&nbsp;</span><span style="color: #DD0000">"dos"</span><span style="color: #007700">,&nbsp;</span><span style="color: #DD0000">"tres"</span><span style="color: #007700">,&nbsp;</span><span style="color: #DD0000">"cuatro"</span><span style="color: #007700">,&nbsp;</span><span style="color: #DD0000">"cinco"</span><span style="color: #007700">);<br /><br /></span><span style="color: #0000BB">$d&nbsp;</span><span style="color: #007700">=&nbsp;</span><span style="color: #0000BB">array_map</span><span style="color: #007700">(</span><span style="color: #0000BB">null</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">$a</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">$b</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">$c</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">print_r</span><span style="color: #007700">(</span><span style="color: #0000BB">$d</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">?&gt;</span>
</span>
</pre></div>
</div>
<div class="example-contents"><p>以上例程会输出：</p></div>
<div class="example-contents screen">
<div class="cdata"><pre>
Array
(
[0] =&gt; Array
(
[0] =&gt; 1
[1] =&gt; one
[2] =&gt; uno
)
[1] =&gt; Array
(
[0] =&gt; 2
[1] =&gt; two
[2] =&gt; dos
)
[2] =&gt; Array
(
[0] =&gt; 3
[1] =&gt; three
[2] =&gt; tres
)
[3] =&gt; Array
(
[0] =&gt; 4
[1] =&gt; four
[2] =&gt; cuatro
)
[4] =&gt; Array
(
[0] =&gt; 5
[1] =&gt; five
[2] =&gt; cinco
)
)
</pre></div>
</div>
</div>
</p>
<p class="para">
如果仅传入一个数组，键（key）会保留；传入多个数组，键（key）是整型数字的序列。
</p>
<p class="para">
<div class="example" id="example-6045">
<p><strong>Example #5 <span class="function"><strong>array_map()</strong></span> 键（key）是 string</strong></p>
<div class="example-contents">
<div class="phpcode"><pre><span style="color: #000000">
<span style="color: #0000BB">&lt;?php<br />$arr&nbsp;</span><span style="color: #007700">=&nbsp;array(</span><span style="color: #DD0000">"stringkey"&nbsp;</span><span style="color: #007700">=&gt;&nbsp;</span><span style="color: #DD0000">"value"</span><span style="color: #007700">);<br />function&nbsp;</span><span style="color: #0000BB">cb1</span><span style="color: #007700">(</span><span style="color: #0000BB">$a</span><span style="color: #007700">)&nbsp;{<br />&nbsp;&nbsp;&nbsp;&nbsp;return&nbsp;array&nbsp;(</span><span style="color: #0000BB">$a</span><span style="color: #007700">);<br />}<br />function&nbsp;</span><span style="color: #0000BB">cb2</span><span style="color: #007700">(</span><span style="color: #0000BB">$a</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">$b</span><span style="color: #007700">)&nbsp;{<br />&nbsp;&nbsp;&nbsp;&nbsp;return&nbsp;array&nbsp;(</span><span style="color: #0000BB">$a</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">$b</span><span style="color: #007700">);<br />}<br /></span><span style="color: #0000BB">var_dump</span><span style="color: #007700">(</span><span style="color: #0000BB">array_map</span><span style="color: #007700">(</span><span style="color: #DD0000">"cb1"</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">$arr</span><span style="color: #007700">));<br /></span><span style="color: #0000BB">var_dump</span><span style="color: #007700">(</span><span style="color: #0000BB">array_map</span><span style="color: #007700">(</span><span style="color: #DD0000">"cb2"</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">$arr</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">$arr</span><span style="color: #007700">));<br /></span><span style="color: #0000BB">var_dump</span><span style="color: #007700">(</span><span style="color: #0000BB">array_map</span><span style="color: #007700">(</span><span style="color: #0000BB">null</span><span style="color: #007700">,&nbsp;&nbsp;</span><span style="color: #0000BB">$arr</span><span style="color: #007700">));<br /></span><span style="color: #0000BB">var_dump</span><span style="color: #007700">(</span><span style="color: #0000BB">array_map</span><span style="color: #007700">(</span><span style="color: #0000BB">null</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">$arr</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">$arr</span><span style="color: #007700">));<br /></span><span style="color: #0000BB">?&gt;</span>
</span>
</pre></div>
</div>
<div class="example-contents"><p>以上例程会输出：</p></div>
<div class="example-contents screen">
<div class="cdata"><pre>
array(1) {
[&quot;stringkey&quot;]=&gt;
array(1) {
[0]=&gt;
string(5) &quot;value&quot;
}
}
array(1) {
[0]=&gt;
array(2) {
[0]=&gt;
string(5) &quot;value&quot;
[1]=&gt;
string(5) &quot;value&quot;
}
}
array(1) {
[&quot;stringkey&quot;]=&gt;
string(5) &quot;value&quot;
}
array(1) {
[0]=&gt;
array(2) {
[0]=&gt;
string(5) &quot;value&quot;
[1]=&gt;
string(5) &quot;value&quot;
}
}
</pre></div>
</div>
</div>
</p>
</div>
<div class="refsect1 seealso" id="refsect1-function.array-map-seealso">
<h3 class="title">参见</h3>
<p class="para">
<ul class="simplelist">
<li class="member"><span class="function"><a href="array_filter.html" class="function" rel="rdfs-seeAlso">array_filter()</a> - 用回调函数过滤数组中的单元</span></li>
<li class="member"><span class="function"><a href="array_reduce.html" class="function" rel="rdfs-seeAlso">array_reduce()</a> - 用回调函数迭代地将数组简化为单一的值</span></li>
<li class="member"><span class="function"><a href="array_walk.html" class="function" rel="rdfs-seeAlso">array_walk()</a> - 使用用户自定义函数对数组中的每个元素做回调处理</span></li>
<li class="member"><a href="language.pseudo-types.html#language.types.callback" class="link">callback</a> 类型的信息</li>
</ul>
</p>
</div>
</div></div></div></body></html>
Reference in New Issue View Git Blame Copy Permalink