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Описание

array array_intersect ( array array1, array array2 [, array ...] )

Функция array_intersect() возвращает массив, содержащий значения массива array1, которые содержат все перечисленные в аргументах массивы. Обратите внимание, что ключи сохраняются.

Пример 1. Пример использования array_intersect()

$array1 = array ("a" => "green", "red", "blue"); $array2 = array ("b" => "green", "yellow", "red"); $result = array_intersect ($array1, $array2);
В результате выполнения переменная $result будет содержать

Array ( [a] => green [0] => red )

Замечание: Два элемента считаются одинаковыми тогда и только тогда, когда (string) $elem1 === (string) $elem2. Другими словами, когда их строковые представления идентичны.

См.также array_diff().

add a note User Contributed Notes
array_intersect

aaron
17-Dec-2006 09:36


this one will work with associative arrays.  also an overwrite function to only replace those elements in the first array.



<?php



function array_union()

{

    if (func_num_args() < 2) { return; }

    $arrays = func_get_args();

    $outputArray = array_shift($arrays);

    $remaining = count($arrays);

    for ($i=0; $i<$remaining; $i++)

    {

        $nextArray = $arrays[$i];

        foreach ($nextArray as $key=>$value)

        {

            $outputArray[$key] = $value;

        }

    }

    return $outputArray;

}



function array_overwrite()

{

    if (func_num_args() < 2) { return; }

    $arrays = func_get_args();

    $outputArray = array_shift($arrays);

    $remaining = count($arrays);

    for ($i=0; $i<$remaining; $i++)

    {

        $nextArray = $arrays[$i];

        foreach ($nextArray as $key=>$value)

        {

            if (array_key_exists($key, $outputArray)) {    $outputArray[$key] = $value; }

        }

    }

    return $outputArray;

}



?>

Niels
19-Sep-2006 04:53


Here is a array_union($a, $b):



<?php

                                        //  $a = 1 2 3 4

    $union =                            //  $b =   2   4 5 6

        array_merge(

            array_intersect($a, $b),    //         2   4

            array_diff($a, $b),         //       1   3

            array_diff($b, $a)          //               5 6

        );                              //  $u = 1 2 3 4 5 6

?>

nthitz at gmail dot com
08-Jun-2006 09:09


I did some trials and if you know the approximate size of the arrays then it would seem to be a lot faster to do this <?php array_intersect($smallerArray, $largerArray); ?> Where $smallerArray is the array with lesser items. I only tested this with long strings but I would imagine that it is somewhat universal.

terry(-at-)shuttleworths(-dot-)net
07-Feb-2006 07:42


I couldn't get array_intersect to work with two arrays of identical objects, so I just did this:



foreach ($firstarray as $key=>$value){

    if (!in_array($value,$secondarray)){

        unset($firstarray[$key]);

    }

}



This leaves $firstarray as the intersection.



Seems to work fine & reasonably quickly.

tom p
04-Nov-2005 06:54


If you store a string of keys in a database field and want to match them to a static array of values, this is a quick way to do it without loops:



<?



$vals = array("Blue","Green","Pink","Yellow");

$db_field = "0,2,3";



echo implode(", ", array_flip(array_intersect(array_flip($vals), explode(",", $db_field))));



// will output "Blue, Pink, Yellow"



?>

sapenov at gmail dot com
10-Jun-2005 01:11


If you need to supply arbitrary number of arguments 

to array_intersect() or other array function, 

use following function:



$full=call_user_func_array('array_intersect', $any_number_of_arrays_here);

SETS INTERSECTION
18-May-2005 11:19


$a = array(1,2,3,4,5,2,6,1);  /* repeated elements --> $a is not a set */

$b = array(0,2,4,6,8,5,7,9,2,1);  /* repeated elements --> $b is not a set */



$ua = array_merge(array_unique($a));  /* now, $a is a set */

$ub = array_merge(array_unique($b));  /* now, $b is a set */



$intersect = array_merge(array_intersect($ua,$ub));



Note: 'array_merge' removes blank spaces in the arrays.

Note: order doesn't matter.



In one line:



$intersect_a_b = array_merge(array_intersect(array_merge(array_unique($a)), array_merge(array_unique($b))));



Additions/corrections wellcome...



gRiNgO

drew at iws dot co dot nz
21-Apr-2005 08:04


Just a handy tip. 



If you want to produce an array from two seperate arrays on their intersects, here you go:



<?



$a = array("branches","E_SHOP");

$b = array("E_SHOP","Webdirector_1_0");



print join("/",array_merge(array_diff($a, $b), array_intersect($a, $b), array_diff($b, $a)));



?>



Gives you:



/branches/E_SHOP/Webdirectory_1_0

blu at dotgeek dot org
14-Oct-2004 05:34


Note that array_intersect and array_unique doesnt work well with multidimensional arrays.

If you have, for example, 



<?php



$orders_today[0] = array('John Doe', 'PHP Book');

$orders_today[1] = array('Jack Smith', 'Coke');



$orders_yesterday[0] = array('Miranda Jones', 'Digital Watch');

$orders_yesterday[1] = array('John Doe', 'PHP Book');

$orders_yesterday[2] = array('Z