php arrays - in_array and/or array_intersect

Answer 1

Do it like this:

<?php
$array1 = array('1','2','3','4');
$array2 = array('1','3','5','7');

//case 1:
print_r(array_intersect($array1, $array2));

//case 2:
print_r(array_diff($array2, $array1));
?>

This outputs the values of array (what you wanted earlier before question was changed):

Array
(
    [0] => 1
    [2] => 3
)
Array
(
    [2] => 5
    [3] => 7
)

---

And, if you want to use if-else, do it like this:

<?php
$array1 = array('1','2','3','4');
$array2 = array('1','3','5','7');

$intesect = array_intersect($array1, $array2);

if(count($intesect))
{
    echo 'the needle';
    print_r($intesect);
}
else
{
    echo'the haystack LESS the needle ';
    print_r(array_diff($array2, $array1));
}
?>

This outputs:

the needle
Array
(
    [0] => 1
    [2] => 3
)