archived-doc-zh/reference/array/functions/array-intersect-key.xml

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<refentry xml:id="function.array-intersect-key" xmlns="http://docbook.org/ns/docbook">
 <refnamediv>
  <refname>array_intersect_key</refname>
  <refpurpose>使用键名比较计算数组的交集</refpurpose>
 </refnamediv>
 <refsect1 role="description">
  &reftitle.description;
  <methodsynopsis>
   <type>array</type><methodname>array_intersect_key</methodname>
   <methodparam><type>array</type><parameter>array1</parameter></methodparam>
   <methodparam><type>array</type><parameter>array2</parameter></methodparam>
   <methodparam choice="opt"><type>array</type><parameter> ...</parameter></methodparam>
  </methodsynopsis>
  <para>
   <function>array_intersect_key</function> 返回一个数组，该数组包含了所有出现在
   <parameter>array1</parameter> 中并同时出现在所有其它参数数组中的键名的值。
  </para>
  <para>
   <example>
    <title><function>array_intersect_key</function> 例子</title>
    <programlisting role="php">
<![CDATA[
<?php
$array1 = array('blue'  => 1, 'red'  => 2, 'green'  => 3, 'purple' => 4);
$array2 = array('green' => 5, 'blue' => 6, 'yellow' => 7, 'cyan'   => 8);

var_dump(array_intersect_key($array1, $array2));
?>
]]>
    </programlisting>
    &example.outputs;
    <screen>
<![CDATA[
array(2) {
  ["blue"]=>
  int(1)
  ["green"]=>
  int(3)
})
]]>
    </screen>
   </example>
  </para>
  <para>
   上例中可以看到只有 <literal>'blue'</literal>
   和 <literal>'green'</literal> 两个键名出现在两个数组中，因此被返回。此外注意
   <literal>'blue'</literal> 和 <literal>'green'</literal>
   的值在两个数组中是不同的。但因为只检查键名，因此还是匹配。返回的值只是
   <parameter>array1</parameter> 中的。
  </para>
  <para>
   在 <literal>key =&gt; value</literal> 对中的两个键名仅在
   <literal>(string) $key1 === (string) $key2 </literal>
   时被认为相等。换句话说，执行的是严格类型检查，因此字符串的表达必须完全一样。
  </para>
  <para>
   参见
   <function>array_diff</function>，<function>array_udiff</function>，<function>array_diff_assoc</function>，<function>array_diff_uassoc</function>，<function>array_udiff_assoc</function>，<function>array_udiff_uassoc</function>，<function>array_diff_key</function>，<function>array_diff_ukey</function>，<function>array_intersect</function>，<function>array_intersect_assoc</function>，<function>array_intersect_uassoc</function>
   和
   <function>array_intersect_ukey</function>。
  </para>
 </refsect1>

 <refsect1 role="parameters">
  &reftitle.parameters;
  <para>
   <variablelist>
    <varlistentry>
     <term><parameter>array1</parameter></term>
     <listitem>
      <para>
       The array with master keys to check.
      </para>
     </listitem>
    </varlistentry>
    <varlistentry>
     <term><parameter>array2</parameter></term>
     <listitem>
      <para>
       An array to compare keys against.
      </para>
     </listitem>
    </varlistentry>
    <varlistentry>
     <term><parameter>array</parameter></term>
     <listitem>
      <para>
       A variable list of arrays to compare.
      </para>
     </listitem>
    </varlistentry>
   </variablelist>
  </para>
 </refsect1>

 <refsect1 role="returnvalues">
  &reftitle.returnvalues;
  <para>
   Returns an associative array containing all the entries of 
   <parameter>array1</parameter> which have keys that are present in all
   arguments.
  </para>      
 </refsect1>

 <refsect1 role="examples">
  &reftitle.examples;
  <para>
   <example>
    <title><function>array_intersect_key</function> example</title>
    <programlisting role="php">
<![CDATA[
<?php
$array1 = array('blue'  => 1, 'red'  => 2, 'green'  => 3, 'purple' => 4);
$array2 = array('green' => 5, 'blue' => 6, 'yellow' => 7, 'cyan'   => 8);

var_dump(array_intersect_key($array1, $array2));
?>
]]>
    </programlisting>
    &example.outputs;
    <screen>
<![CDATA[
array(2) {
  ["blue"]=>
  int(1)
  ["green"]=>
  int(3)
}
]]>
    </screen>
   </example>
  </para>
  <para>
   In our example you see that only the keys <literal>'blue'</literal>
   and <literal>'green'</literal> are present in both arrays and thus
   returned. Also notice that the values for the keys
   <literal>'blue'</literal> and <literal>'green'</literal> differ between
   the two arrays. A match still occurs because only the keys are checked.
   The values returned are those of <parameter>array1</parameter>.
  </para>
  <para>
   The two keys from the <literal>key =&gt; value</literal> pairs are
   considered equal only if
   <literal>(string) $key1 === (string) $key2 </literal>. In other words
   a strict type check is executed so the string representation must be
   the same.
  </para>
 </refsect1>

 <refsect1 role="seealso">
  &reftitle.seealso;
  <para>
   <simplelist>
    <member><function>array_diff</function></member>
    <member><function>array_udiff</function></member>
    <member><function>array_diff_assoc</function></member>
    <member><function>array_diff_uassoc</function></member>
    <member><function>array_udiff_assoc</function></member>
    <member><function>array_udiff_uassoc</function></member>
    <member><function>array_diff_key</function></member>
    <member><function>array_diff_ukey</function></member>
    <member><function>array_intersect</function></member>
    <member><function>array_intersect_assoc</function></member>
    <member><function>array_intersect_uassoc</function></member>
    <member><function>array_intersect_ukey</function></member>
   </simplelist>
  </para>
 </refsect1>
</refentry>

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