Question

I have :

$a = array(
    0=>'you',
    1=>'will',
    2=>'be',
    3=>'so',
    4=>'happy',
    5=>'in'
);

$b = array(
    0=>'1',
    1=>'4',
    2=>'5'
);   // (KEYS:1,4,5)

I want out the values of $a that matches $b’s keys;

so $val would be willhappyin.

And then comma-separate them.. like: will,happy,in without comma after last one.

How can i do this ? 🙂

Answer 1

$string = implode(",", array_intersect_key($a, array_flip($b)));

EXPLANATION:

array_flip switches the values of $b to keys.

array_intersect_key takes only the entries in $a that are also present in $b.

implode joins the resulting array values together by comma.