PHP - array_diff比较和删除所有类似的值

Question

I would appreciate a little help . I have tried array_diff(), intersect combos but not able to get my expected return.

Here is an example what i want to do.

First array.

Array
(
    [0] => 21
    [1] => 2
    [2] => 1
    [3] => 2
)

Second array

Array
(
    [0] => 21
    [1] => 2
)

using array_diff(firstarray, secondarray) i get following.

Array
(
    [2] => 1
)

But what i want

Array
(
    [2] => 1
    [3] => 2
)

keys from firstarray and secondarray wont necessarily be same.

Answer 1

This little snippet should help you achieve what you want. Here we'll loop the second array, and remove the first occurrence of each value it finds from the first array.

$first = array(0 => 21, 1 => 2, 2 => 1, 3 => 2);
$second = array(0 => 21, 1 => 2);

foreach ($second as $v) {
    unset($first[array_search($v, $first)]);
}

Output from $first after looping:

Array
(
    [2] => 1
    [3] => 2
)

If you wish to keep the $first array intact, copy it into an other variable, and loop that, i.e. $new = $first; and unset from $new instead of $first.

Live demo

• http://php.net/manual/en/function.array-search.php