I want to compare two comma delimited strings in PHP and keep only the values that appear in both -

i have 2 comma delimited strings integers. 1 ids of article types script being called told display (by post) , other ids of article types current logged in user has permission see.

i want generate third comma separated list of integers values appear in both. e.g.:

$want_to_see = "1,5,6,8,10"  $current_user_can_see = "1,3,6,10,20"  $show = "1,6,10" 

you can break 2 strings arrays using explode, , use array_intersect keep common values:

$want_to_see = explode(",", "1,5,6,8,10"); $current_user_can_see = explode(",", "1,3,6,10,20")  // array of common elements: $show = array_intersect($want_to_see, $current_user_can_see);  // if want string: $show_str = implode(",", $show);