Python: Tuple (Solutions)

1. Solutions:

   couple_of_int = (0, 1)
   print type(couple_of_int)            # tuple
   
   
   couple_of_strings = ("one", "tuple")
   print type(couple_of_strings)          # tuple
   
   
   a_single_element = (0,)
   print type(a_single_element)            # tuple
   print len(a_single_element)             # 1
   
   a_single_element_alt = tuple([0])
   print type(a_single_element_alt)        # tuple
   print len(a_single_element_alt)         # 1
   
   wrong = (0)
   print type(wrong)                   # int
   print len(wrong)                    # error!
   
   
   hundred_elements = tuple(range(100))
   print type(hundred_elements)              # tuple
   
   
   tuple_of_lists = (range(50), range(50, 100))
   print type(tuple_of_lists)
   print type(tuple_of_lists[0])
   
   
   tuple_of_tuples = (tuple(range(50)), tuple(range(50, 100)))
   print type(tuple_of_tuples)
   print type(tuple_of_tuples[0])
   

2. Solutions:

   l = [0, 1, 2]
   t = (0, 1, 2)
   
   # x refers to a list, the code replaces
   # the first element with 100
   x = l
   x[0] = 100
   
   # x now refers to a tuple, that is immutable:
   # we cannot replace its elements, Python raises an error message
   x = t
   x[0] = 100                          # error!
   

3. Solutions:

   tup = (0, 1, 2, [3, 4, 5], 6, 7, 8)
   
   print tup[0]                      # 0
   print type(tup[0])                # int
   
   print tup[3]                      # [3, 4, 5]
   print type(tup[3])                # list
   
   print len(tup)                    # 9
   
   print len(tup[3])                 # 3
   
   tup[3][-1] = "last"
   print tup
   # yes, we can do it, we "modified" the tuple
   # by modifying the list contained in it.
   
   
   tup[-1] = "last"                # error!
   # we cannot modify the tuple "directly"
   # it's an immutable object