php compare two arrays and order output by ref

Question

I have arrays order (list) by ref :

$a = array('Blue', 'Red', 'Orange', 'Yellow');

And new elements (mixing order + new element) :

$b = array('Orange', 'Blue', 'Yellow', 'Red', 'Pink');

I want my outcome ($b) to be, like in $a order + new(s) element(s) :

Result : Array
 (
 [0] => Blue
 [1] => Red
 [2] => Orange
 [3] => Yellow
 [4] => Pink
 )

Any idea in language reference ?

Answer 1

If you want to preserve array indexes doing $a + difference($b-a)

$a = array('Blue', 'Red', 'Orange', 'Yellow');
$b = array('Orange', 'Blue', 'Yellow', 'Red', 'Pink');

$merged = array_merge($a, array_diff($b, $a));
print_r($merged);

outputs

Array
    (
        [0] => Blue
        [1] => Red
        [2] => Orange
        [3] => Yellow
        [4] => Pink
    )

If you're not interested in keeping keys values you can also use array_unique with an array_merge:

$merged = array_unique(array_merge($a, $b)));
print_r($merged);

outputs:

Array
(
    [0] => Blue
    [1] => Red
    [2] => Orange
    [3] => Yellow
    [8] => Pink
)