# final_considerations.py >>> a = 1000000 >>> b = 1000000 >>> id(a) == id(b) False >>> a = 5 >>> b = 5 >>> id(a) == id(b) True # how to choose data structures # example customer objects customer1 = {'id': 'abc123', 'full_name': 'Master Yoda'} customer2 = {'id': 'def456', 'full_name': 'Obi-Wan Kenobi'} customer3 = {'id': 'ghi789', 'full_name': 'Anakin Skywalker'} # collect them in a tuple customers = (customer1, customer2, customer3) # or collect them in a list customers = [customer1, customer2, customer3] # or maybe within a dictionary, they have a unique id after all customers = { 'abc123': customer1, 'def456': customer2, 'ghi789': customer3, } # negative indexing >>> a = list(range(10)) # `a` has 10 elements. Last one is 9. >>> a [0, 1, 2, 3, 4, 5, 6, 7, 8, 9] >>> len(a) # its length is 10 elements 10 >>> a[len(a) - 1] # position of last one is len(a) - 1 9 >>> a[-1] # but we don't need len(a)! Python rocks! 9 >>> a[-2] # equivalent to len(a) - 2 8 >>> a[-3] # equivalent to len(a) - 3 7