This is terribly misguided.

You do know that PHP has built-in min and max functions, right?

  And array_map. 
  And array_walk. 
  And array_filter. 
  And array_reduce. 
  And array_slice. 
  And array_unique. 
  And array_search. 
  And range. 
  And empty. 
  And is_object. 
  And is_array.