array.xml

<?xml version="1.0" encoding="utf-8"?>
<sect1 xml:id="language.operators.array">
 <title>Array Operators</title>
 <titleabbrev>Array</titleabbrev>
 <table>
  <title>Array Operators</title>
  <tgroup cols="3">
   <thead>
    <row>
     <entry>Example</entry>
     <entry>Name</entry>
     <entry>Result</entry>
    </row>
   </thead>
   <tbody>
    <row>
     <entry>$a + $b</entry>
     <entry>Union</entry>
     <entry>Union of <varname>$a</varname> and <varname>$b</varname>.</entry>
    </row>
    <row>
     <entry>$a == $b</entry>
     <entry>Equality</entry>
     <entry>&true; if <varname>$a</varname> and <varname>$b</varname> have the same key/value pairs.</entry>
    </row>
    <row>
     <entry>$a === $b</entry>
     <entry>Identity</entry>
     <entry>&true; if <varname>$a</varname> and <varname>$b</varname> have the same key/value pairs in the same
      order and of the same types.</entry>
    </row>
    <row>
     <entry>$a != $b</entry>
     <entry>Inequality</entry>
     <entry>&true; if <varname>$a</varname> is not equal to <varname>$b</varname>.</entry>
    </row>
    <row>
     <entry>$a &lt;&gt; $b</entry>
     <entry>Inequality</entry>
     <entry>&true; if <varname>$a</varname> is not equal to <varname>$b</varname>.</entry>
    </row>
    <row>
     <entry>$a !== $b</entry>
     <entry>Non-identity</entry>
     <entry>&true; if <varname>$a</varname> is not identical to <varname>$b</varname>.</entry>
    </row>
   </tbody>
  </tgroup>
 </table>
 <para>
  The <literal>+</literal> operator returns the right-hand array appended
  to the left-hand array; for keys that exist in both arrays, the elements
  from the left-hand array will be used, and the matching elements from the
  right-hand array will be ignored.
 </para>
 <para>
  <example>
   <title>Array Append Operator</title>
   <programlisting role="php">
<![CDATA[
<?php
$a = array("a" => "apple", "b" => "banana");
$b = array("a" => "pear", "b" => "strawberry", "c" => "cherry");

$c = $a + $b; // Union of $a and $b
echo "Union of \$a and \$b: \n";
var_dump($c);

$c = $b + $a; // Union of $b and $a
echo "Union of \$b and \$a: \n";
var_dump($c);

$a += $b; // Union of $a += $b is $a and $b
echo "Union of \$a += \$b: \n";
var_dump($a);
?>
]]>
   </programlisting>
   &example.outputs;
   <screen role="php">
<![CDATA[
Union of $a and $b:
array(3) {
  ["a"]=>
  string(5) "apple"
  ["b"]=>
  string(6) "banana"
  ["c"]=>
  string(6) "cherry"
}
Union of $b and $a:
array(3) {
  ["a"]=>
  string(4) "pear"
  ["b"]=>
  string(10) "strawberry"
  ["c"]=>
  string(6) "cherry"
}
Union of $a += $b:
array(3) {
  ["a"]=>
  string(5) "apple"
  ["b"]=>
  string(6) "banana"
  ["c"]=>
  string(6) "cherry"
}
]]>
   </screen>
  </example>
 </para>
 <para>
  Elements of arrays are equal for the comparison if they have the
  same key and value.
 </para>
 <para>
  <example>
   <title>Comparing arrays</title>
   <programlisting role="php">
<![CDATA[
<?php
$a = array("apple", "banana");
$b = array(1 => "banana", "0" => "apple");

var_dump($a == $b); // bool(true)
var_dump($a === $b); // bool(false)
?>
]]>
   </programlisting>
  </example>
 </para>

 <sect2 role="seealso">
  &reftitle.seealso;
  <para>
   <simplelist>
    <member><link linkend="language.types.array">Array type</link></member>
    <member><link linkend="ref.array">Array functions</link></member>
   </simplelist>
  </para>
 </sect2>
</sect1>