Finding cartesian product with PHP associative arrays

Question

Say that I have an array like the following:

Array
(
    [arm] => Array
        (
            [0] => A
            [1] => B
            [2] => C
         


        

Answer 1

Why not use a database to do this?

It's easy in MySQL..

table arm
   id integer primary key
   label char

table gender
   id integer primary key
   gender enum('male','female')

table location
   id integer primary key
   city varchar(255)

Then do a query

$query = mysql_query(" 
  SELECT a.label, g.gender, l.city
  FROM arm a
  CROSS JOIN gender g
  CROSS JOIN location l
  ORDER BY a.id
") or die("Could not execute query");

while($row = mysql_fetch_array($query) )
{
   ....
}

And read that out: