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12.8 List Methods

        Python provides several methods to manipulate lists. Below, we will discuss some of these methods with an example
        list: lst. These methods do not create a new list; they modify the original list: lst. Such an operation that takes place
        on an existing object is said to be in place.
        ●  lst.append(elem): The method append() inserts the object elem, passed as an argument, at the end of
           the list lst.
          Example:

         >>> lst1 = [10, 20, 30, 40]
         >>> lst1.append(35)
         >>> lst1
              [10, 20, 30, 40, 35]
        ●  lst.insert(index, elem): The method insert() inserts the object elem, passed as an argument, at the
           specified index.
          Example:

         >>> names = ['Aryan', 'Anthony', 'Sunpreet', 'Venkatesh']
         >>> names.insert(2, 'Samantha')
         >>> names
              ['Aryan', 'Anthony', 'Samantha', 'Sunpreet',  'Venkatesh']
        ●  lst.extend(obj): The method extend() inserts the elements in obj, passed as an argument, at the end of the
           elements of the list lst. Note that obj may not necessarily be a list and could as well be a tuple, set, or dictionary.

          Example:
         >>> intList = [10, 20, 30]
         >>> intList.extend([40,50])
         >>> intList
              [10, 20, 30, 40, 50]
          C T  02     Assuming that lst is a list, what is the difference between the operations?

                      lst.extend([40,50]) and lst + [40, 50]




         >>> 1st = [1, 2, 3]
         >>> 1st.extend([4, 5])
         >>> 1st
              [1, 2, 3, 4, 5]
         >>> 1st = [1, 2, 3]
         >>> 1st + [4, 5]
              [1, 2, 3, 4, 5]
         >>> 1st
              [1, 2, 3]
        ●  lst.index(elem): The method index() returns the index of the first occurrence of the element elem in the
           list. If elem does not appear in the list lst, it throws a ValueError, for example,

         >>> names = ['Aryan', 'Anthony', 'Samantha', 'Sunpreet', 'Venkatesh']
         >>> names.index('Samantha')
              2
         >>> name = 'Arjun'
         >>> names.index(name)
              Traceback (most recent call last):
                File '<pyshell#3>', line 1, in <module>
                  names.index(name)
              ValueError: 'Arjun' is not in list
        Note: To avoid ValueError, we can use the membership operator to check the membership of an element.


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