Page 152 - Computer Science Class 11 Without Functions
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●  Tuples
        A tuple is a sequence of objects (not necessarily of the same type) enclosed in parenthesis: (). Just like lists, data
        items in a tuple are separated by commas (,). However, there is a striking difference between a list and a tuple. A tuple
        is an immutable object, i.e., once created, the values in a tuple cannot be changed using an assignment operator. In
        contrast, we have already seen that a list is a mutable object, i.e., the values in a list can be easily changed using an
        assignment operator.
         >>> vowels = ('a','e','i','o','u')
         >>> vowels
              ('a', 'e', 'i', 'o', 'u')
         >>> weekDays  = ('Monday', 'Tusday', 'Wednesday', 'Thursday', 'Friday')
         >>> weekDays
              ('Monday', 'Tusday', 'Wednesday', 'Thursday', 'Friday')
                On realising that you wrongly typed Tuesday, it would be tempting to modify weekDays[1]
              to 'Tuesday'
         >>> weekDays[1] =  'Tuesday'

              Traceback (most recent call last):
                File "<pyshell#101>", line 1, in <module>
                weekDays[1] =  'Tuesday'
              TypeError: 'tuple' object does not support item assignment
        Note that an attempt to modify an element of a tuple has resulted in a type error because we have applied an illegal
        operation to a tuple.

        7.1.4 Set

        A  set  is  an  unordered  and  unindexed  collection  of  data  items  separated  by  a  comma  and  enclosed  within  curly
        brackets:{}. Unlike a list, a set cannot have duplicate values. For example,

         >>> set1 = {1, 2, 3, 4}
         >>> set1
              {1, 2, 3, 4}
         >>> set2 = {1, 2, 3, 5, 1, 6, 2}
         >>> set2
              {1, 2, 3, 5, 6}
        Note that the duplicate entries in set2 have been removed. A set may be modified using the operator |=. As follows:
         >>> s = {1, 29, 4}
         >>> id(s)
              2309188291712
         >>> s = {54, 9}/s |= {54, 9}
         >>> s
              {1, 4, 54, 9, 29}
         >>> id(s)
              2309188291712
        7.1.5 None

        NoneType has a single value: None. It is used to signify the absence of value in a given statement. None supports
        no special operations. The value of None is neither False nor 0 (zero). Consider the following examples:

         >>> type(None)
              <class 'NoneType'>
         >>> print(None)
              None
        However, if you execute the command,

              None
        Nothing is printed. In a logical expression, the value of None is False.


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