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Python: Tuple (Solutions)
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#. 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])

#. 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!

#. 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