PHP Array Intersect dont include empty arrays

Question

I have 4 arrays, which are going to be different every time I run my code. Sometimes, maybe empty. I am using array_intersect to get the common value from the set of arrays and if any one of the array is empty it returns me an empty array. I want array_intersect to ignore empty array's.

Example:

$array1 = array('441', '442', '443');
$array2 = array('441', '443');
$array3 = array('441', '442',);
$array4 = array();

var_dump(array_intersect($array1, $array2, $array3, $array4));

// Returns
array('');

// Required
array('441');

How do I make it ignore $array4 and give an output of 441

This is how the function works. And everything else would not make sense. You need to check if your array is empty before you call the function - and then either include it in the list of parameters, or not. — C3roe
– C3roe, Commented Oct 4, 2017 at 12:38
I know, but that what I exactly asked in the question. How do I make array_intersect ignore the empty array — Zain Sohail
– Zain Sohail, Commented Oct 4, 2017 at 12:38

Lawrence Cherone · Accepted Answer · 2017-10-04 12:43:02Z

15

If you store your arrays as an array you can do this:

<?php
// create array of arrays
$array[] = array('441', '442', '443');
$array[] = array('441', '443');
$array[] = array('441', '442');
$array[] = array();

// filter out empty array
$array = array_filter($array);

// pass in array (inline argument unpacking PHP > 5.6)
print_r(array_intersect(...$array));

Array
(
    [0] => 441
)

https://3v4l.org/MD3r2

answered Oct 4, 2017 at 12:43

Lawrence Cherone

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Fahad Sohail · Accepted Answer · 2017-10-04 12:42:42Z

2

$tempArray = [];
if (count($g_arr) >0) $tempArray[] = $g_arr;
if (count($c_arr) >0) $tempArray[] = $c_arr;
if (count($k_arr) >0) $tempArray[] = $k_arr;
if (count($m_arr) >0) $tempArray[] = $m_arr;
if (count($p_arr) >0) $tempArray[] = $p_arr;

$intersect = call_user_func_array('array_intersect', $tempArray);

answered Oct 4, 2017 at 12:42

Fahad Sohail

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2 Comments

Emy Ferreira Over a year ago

That's a bad practice I think !

GrumpyCrouton Over a year ago

Why count()? You could just check if it's empty(), and these variable names are not descriptive in the slightest

Chetan Ameta · Accepted Answer · 2017-10-04 13:04:37Z

2

Have a look on below solution:

$array = array(); //initialize $arrar
$array[] = array('441', '442', '443');
$array[] = array('441', '443');
$array[] = array('441', '442',);
$array[] = array();
$array = array_filter($array); //filter empty array
$res_arr = array_shift($array); // Shift an element off the beginning of array
foreach($array as $filter){
        $res_arr = array_intersect($res_arr, $filter);
}

print_r($res_arr);

Output

Array ( [0] => 441 )

See example at: https://3v4l.org/Rkt1R

edited Oct 4, 2017 at 13:04

answered Oct 4, 2017 at 12:54

Chetan Ameta

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Comments

Kevin R · Accepted Answer · 2017-10-04 13:01:08Z

1

$array1 = array('441', '442', '443');
$array2 = array('441', '443');
$array3 = array('441', '442',);
$array4 = array();


function get_intersect(...$arrays){
    $instersect_arrays = array();

    foreach($arrays as $array){
        if(!empty($array)){
            array_push($instersect_arrays,$array);
        }
    }

    return call_user_func_array('array_intersect', $instersect_arrays);
}

var_dump(get_intersect($array1, $array2, $array3, $array4));

//output: array(1) { [0]=> string(3) "441" }

answered Oct 4, 2017 at 13:01

Kevin R

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