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

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<refentry xml:id="function.array-diff-key" xmlns="http://docbook.org/ns/docbook">
   <refnamediv>
    <refname>array_diff_key</refname>
    <refpurpose>使用键名比较计算数组的差集</refpurpose>
   </refnamediv>
 <refsect1 role="description">
  &reftitle.description;
     <methodsynopsis>
      <type>array</type><methodname>array_diff_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_diff_key</function> 返回一个数组，该数组包括了所有出现在
     <parameter>array1</parameter>
     中但是未出现在任何其它参数数组中的键名的值。注意关联关系保留不变。本函数和
     <function>array_diff</function> 相同只除了比较是根据键名而不是值来进行的。
    </para>
    <para>
     <example>
      <title><function>array_diff_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_diff_key($array1, $array2));
?>
]]>
      </programlisting>
      &example.outputs;
      <screen>
<![CDATA[
array(2) {
  ["red"]=>
  int(2)
  ["purple"]=>
  int(4)
}
]]>
      </screen>
     </example>
    </para>
    <simpara>
     在 <literal>key =&gt; value</literal> 对中的两个键名仅在
     <literal>(string) $key1 === (string) $key2 </literal>
     时被认为相等。换句话说，执行的是严格类型检查，因此字符串的表达必须完全一样。
    </simpara>
    <note>
     <simpara>
      注意本函数只检查了多维数组中的一维。当然，可以用
      <literal>array_diff_key($array1[0], $array2[0]);</literal>
      来检查更深的维度。
     </simpara>
    </note>
    <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_ukey</function>，<function>array_intersect</function>，<function>array_intersect_assoc</function>，<function>array_intersect_uassoc</function>，<function>array_intersect_key</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 to compare from
      </para>
     </listitem>
    </varlistentry>

    <varlistentry>
     <term><parameter>array2</parameter></term>
     <listitem>
      <para>
       An array to compare against
      </para>
     </listitem>
    </varlistentry>

    <varlistentry>
     <term><parameter>...</parameter></term>
     <listitem>
      <para>
       More arrays to compare against
      </para>
     </listitem>
    </varlistentry>

   </variablelist>
  </para>
 </refsect1>

 <refsect1 role="returnvalues">
  &reftitle.returnvalues;
  <para>
   Returns an <type>array</type> containing all the entries from
   <parameter>array1</parameter> whose keys are not present in any of the
   other arrays.
  </para>
 </refsect1>

<!--
 <refsect1 role="errors">
  &reftitle.errors;
  &errors.no.unusual.errors;
 </refsect1>
-->

 <refsect1 role="examples">
  &reftitle.examples;
  <para>
   <example>
    <title><function>array_diff_key</function> example</title>
    <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>
    <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_diff_key($array1, $array2));
?>
]]>
    </programlisting>
    &example.outputs;
    <screen>
<![CDATA[
array(2) {
  ["red"]=>
  int(2)
  ["purple"]=>
  int(4)
}
]]>
    </screen>
   </example>
  </para>
 </refsect1>

 <refsect1 role="notes">
  &reftitle.notes;
  <note>
   <para>
    This function only checks one dimension of a n-dimensional
    array. Of course you can check deeper dimensions by using
    <literal>array_diff_key($array1[0], $array2[0]);</literal>.
   </para>
  </note>
 </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_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_key</function></member>
    <member><function>array_intersect_ukey</function></member>
   </simplelist>
  </para>
 </refsect1>
  </refentry>

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