doc-zh/reference/array/functions/array-find-key.xml at 6133dba5cd49530e67fa818d99abfd446c3ba584 · php/doc-zh · GitHub

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
<?xml version="1.0" encoding="utf-8"?>
<!-- $Revision$ -->
<!-- EN-Revision: 596c11440dc232b8ed1836d7e3afe2ed5b225a7b Maintainer: Singi Status: ready -->
<refentry xml:id="function.array-find-key" xmlns="http://docbook.org/ns/docbook">
 <refnamediv>
  <refname>array_find_key</refname>
  <refpurpose>返回满足回调函数条件的第一个元素的键</refpurpose>
 </refnamediv>

 <refsect1 role="description">
  &reftitle.description;
  <methodsynopsis>
   <type>mixed</type><methodname>array_find_key</methodname>
   <methodparam><type>array</type><parameter>array</parameter></methodparam>
   <methodparam><type>callable</type><parameter>callback</parameter></methodparam>
  </methodsynopsis>
  <simpara>
   <function>array_find_key</function> 返回 &array; 中第一个使指定 <parameter>callback</parameter> 返回 &true; 的元素的键。如果未找到匹配元素，则该函数返回 &null;。
  </simpara>
 </refsect1>

 <refsect1 role="parameters">
  &reftitle.parameters;
  <variablelist>
   <varlistentry>
    <term><parameter>array</parameter></term>
    <listitem>
     <simpara>
      需要被遍历的 &array;。
     </simpara>
    </listitem>
   </varlistentry>
   <varlistentry>
    <term><parameter>callback</parameter></term>
    <listitem>
     <para>
      用于检查每个元素的回调函数，该函数必须
      <methodsynopsis>
       <type>bool</type><methodname><replaceable>callback</replaceable></methodname>
       <methodparam><type>mixed</type><parameter>value</parameter></methodparam>
       <methodparam><type>mixed</type><parameter>key</parameter></methodparam>
      </methodsynopsis>
      如果该函数返回 &true;，<function>array_find_key</function> 就会返回对应键名，并且不再对后续元素执行该回调函数。
     </para>
    </listitem>
   </varlistentry>
  </variablelist>
 </refsect1>

 <refsect1 role="returnvalues">
  &reftitle.returnvalues;
  <simpara>
   该函数会返回首个使 <parameter>callback</parameter> 返回 &true; 的元素的键。如果未找到匹配的元素，则函数返回 &null;。
  </simpara>
 </refsect1>

 <refsect1 role="examples">
  &reftitle.examples;
  <example>
   <title><function>array_find_key</function> 示例</title>
   <programlisting role="php">
<![CDATA[
<?php
$array = [
    'a' => 'dog',
    'b' => 'cat',
    'c' => 'cow',
    'd' => 'duck',
    'e' => 'goose',
    'f' => 'elephant'
];

// Find the first animal with a name longer than 4 characters.
var_dump(array_find_key($array, function (string $value) {
    return strlen($value) > 4;
}));

// Find the first animal whose name begins with f.
var_dump(array_find_key($array, function (string $value) {
    return str_starts_with($value, 'f');
}));

// Find the first animal where the array key is the first symbol of the animal.
var_dump(array_find_key($array, function (string $value, $key) {
   return $value[0] === $key;
}));

// Find the first animal where the array key matching a RegEx.
var_dump(array_find_key($array, function ($value, $key) {
   return preg_match('/^([a-f])$/', $key);
}));
?>
]]>
   </programlisting>
   &example.outputs;
   <screen>
<![CDATA[
string(1) "e"
NULL
string(1) "c"
string(1) "a"
]]>
   </screen>
  </example>
 </refsect1>

 <refsect1 role="seealso">
  &reftitle.seealso;
  <simplelist>
   <member><function>array_find</function></member>
   <member><function>array_all</function></member>
   <member><function>array_any</function></member>
   <member><function>array_filter</function></member>
   <member><function>array_reduce</function></member>
  </simplelist>
 </refsect1>
</refentry>
<!-- Keep this comment at the end of the file
Local variables:
mode: sgml
sgml-omittag:t
sgml-shorttag:t
sgml-minimize-attributes:nil
sgml-always-quote-attributes:t
sgml-indent-step:1
sgml-indent-data:t
indent-tabs-mode:nil
sgml-parent-document:nil
sgml-default-dtd-file:"~/.phpdoc/manual.ced"
sgml-exposed-tags:nil
sgml-local-catalogs:nil
sgml-local-ecat-files:nil
End:
vim600: syn=xml fen fdm=syntax fdl=2 si
vim: et tw=78 syn=sgml
vi: ts=1 sw=1
-->