PHP - Multiple uasort functions breaks sorting

Question

I have a multidimensional array that stores people.

Array (
   id93294 => (array (
             Name => \"Tom Anderson\",
             Birthday => \         


        

Answer 1

Excellent question.

This pseudo-code comes from the definition of the problem you gave and is intended to be the callback function given to uasort. I cannot fill in the details because you've omitted the code you're using; hopefully this leads you on the right track.

function compare(p1, p2):
    if birthdays of p1 and p2 are not the same
        compare by birthday
    else
        compare by hometown

If someone could verify that this is a valid comparison function for a sort algorithm in the comments, I would be grateful.