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<refentry xml:id="function.array-udiff" xmlns="http://docbook.org/ns/docbook">
 <refnamediv>
  <refname>array_udiff</refname>
  <refpurpose>Computes the difference of arrays by using a callback function for data comparison</refpurpose>
 </refnamediv>
 <refsect1 role="description">
  &reftitle.description;
  <methodsynopsis>
   <type>array</type><methodname>array_udiff</methodname>
   <methodparam><type>array</type><parameter>array</parameter></methodparam>
   <methodparam rep="repeat"><type>array</type><parameter>arrays</parameter></methodparam>
   <methodparam><type>callable</type><parameter>value_compare_func</parameter></methodparam>
  </methodsynopsis>
  <para>
   Computes the difference of arrays by using a callback function for data
   comparison. This is unlike <function>array_diff</function> which uses an
   internal function for comparing the data.
  </para>
 </refsect1>
 <refsect1 role="parameters">
  &reftitle.parameters;
  <para>
   <variablelist>
    <varlistentry>
     <term><parameter>array</parameter></term>
     <listitem>
      <para>
       The first array.
      </para>
     </listitem>
    </varlistentry>
    <varlistentry>
     <term><parameter>arrays</parameter></term>
     <listitem>
      <para>
       Arrays to compare against.
      </para>
     </listitem>
    </varlistentry>
    <varlistentry>
     <term><parameter>value_compare_func</parameter></term>
     <listitem>
      <para>
       The callback comparison function.
      </para>
      <para>
       &return.callbacksort;
      </para>
      &callback.cmp;
     </listitem>
    </varlistentry>
   </variablelist>
  </para>
 </refsect1>
 <refsect1 role="returnvalues">
  &reftitle.returnvalues;
  <para>
   Returns an array containing all the values of <parameter>array</parameter>
   that are not present in any of the other arguments.
  </para>
 </refsect1>
 <refsect1 role="examples">
  &reftitle.examples;
  <para>
   <example>
    <title><function>array_udiff</function> example using stdClass Objects</title>
    <programlisting role="php">
<![CDATA[
<?php
// Arrays to compare
$array1 = array(new stdclass, new stdclass,
                new stdclass, new stdclass,
               );

$array2 = array(
                new stdclass, new stdclass,
               );

// Set some properties for each object
$array1[0]->width = 11; $array1[0]->height = 3;
$array1[1]->width = 7;  $array1[1]->height = 1;
$array1[2]->width = 2;  $array1[2]->height = 9;
$array1[3]->width = 5;  $array1[3]->height = 7;

$array2[0]->width = 7;  $array2[0]->height = 5;
$array2[1]->width = 9;  $array2[1]->height = 2;

function compare_by_area($a, $b) {
    $areaA = $a->width * $a->height;
    $areaB = $b->width * $b->height;
    
    if ($areaA < $areaB) {
        return -1;
    } elseif ($areaA > $areaB) {
        return 1;
    } else {
        return 0;
    }
}

print_r(array_udiff($array1, $array2, 'compare_by_area'));
?>
]]>
    </programlisting>
    &example.outputs;
    <screen>
<![CDATA[
Array
(
    [0] => stdClass Object
        (
            [width] => 11
            [height] => 3
        )

    [1] => stdClass Object
        (
            [width] => 7
            [height] => 1
        )

)
]]>
    </screen>
   </example>
  </para>
  <para>
   <example>
    <title><function>array_udiff</function> example using DateTime Objects</title>
    <programlisting role="php">
<![CDATA[
<?php
class MyCalendar {
    public $free = array();
    public $booked = array();

    public function __construct($week = 'now') {
        $start = new DateTime($week);
        $start->modify('Monday this week midnight');
        $end = clone $start;
        $end->modify('Friday this week midnight');
        $interval = new DateInterval('P1D');
        foreach (new DatePeriod($start, $interval, $end) as $freeTime) {
            $this->free[] = $freeTime;
        }
    }

    public function bookAppointment(DateTime $date, $note) {
        $this->booked[] = array('date' => $date->modify('midnight'), 'note' => $note);
    }

    public function checkAvailability() {
        return array_udiff($this->free, $this->booked, array($this, 'customCompare'));
    }
    
    public function customCompare($free, $booked) {
        if (is_array($free)) $a = $free['date'];
        else $a = $free;
        if (is_array($booked)) $b = $booked['date'];
        else $b = $booked;
        if ($a == $b) {
            return 0;
        } elseif ($a > $b) {
            return 1;
        } else {
            return -1;
        }
    }
}

// Create a calendar for weekly appointments
$myCalendar = new MyCalendar;

// Book some appointments for this week
$myCalendar->bookAppointment(new DateTime('Monday this week'), "Cleaning GoogleGuy's apartment.");
$myCalendar->bookAppointment(new DateTime('Wednesday this week'), "Going on a snowboarding trip.");
$myCalendar->bookAppointment(new DateTime('Friday this week'), "Fixing buggy code.");

// Check availability of days by comparing $booked dates against $free dates
echo "I'm available on the following days this week...\n\n";
foreach ($myCalendar->checkAvailability() as $free) {
    echo $free->format('l'), "\n"; 
}
echo "\n\n";
echo "I'm busy on the following days this week...\n\n";
foreach ($myCalendar->booked as $booked) {
    echo $booked['date']->format('l'), ": ", $booked['note'], "\n"; 
}
?>
]]>
    </programlisting>
    &example.outputs;
    <screen>
<![CDATA[
I'm available on the following days this week...

Tuesday
Thursday


I'm busy on the following days this week...

Monday: Cleaning GoogleGuy's apartment.
Wednesday: Going on a snowboarding trip.
Friday: Fixing buggy code.
]]>
    </screen>
   </example>
  </para>
 </refsect1>
 <refsect1 role="notes">
  &reftitle.notes;
  <note>
   <simpara>
    Please note that this function only checks one dimension of a n-dimensional
    array. Of course you can check deeper dimensions by using
    <literal>array_udiff($array1[0], $array2[0], "data_compare_func");</literal>.
   </simpara>
  </note>
 </refsect1>
 <refsect1 role="seealso">
  &reftitle.seealso;
  <para>
   <simplelist>
    <member><function>array_diff</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_intersect</function></member>
    <member><function>array_intersect_assoc</function></member>
    <member><function>array_uintersect</function></member>
    <member><function>array_uintersect_assoc</function></member>
    <member><function>array_uintersect_uassoc</function></member>
   </simplelist>
  </para>
 </refsect1>
</refentry>

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