For any or all of said purposes, the council may, by ordinance, divide the city into districts of such number, shape and area as may be deemed best suited to carry out the purposes of this act and, within such districts, they may regulate and restrict the erection, construction, reconstruction, alteration, repair, use or occupancy of buildings, structures or land. All such regulations shall be uniform for each class or kind of buildings, structures or land throughout each district; but the regulations in one district may differ from those in other districts.