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Important Features of Lists

                 Based on the above definition, the list has the following important features:
                    • It is mutable data type.
                    • It is an ordered sequence of values.
                    • Each element is separated by comma and enclosed in square brackets [ ].
                    • Each value/element is accessed by an index number.

                    • The values can be added, modified or deleted by the user throughout the program.
                    • It stores the values of different data types.

                 Creating a List

                 A list is created by enclosing the values within square brackets. Each value/element is separated by a comma
                 and stored under a common name. These values can be of different data types. The name follows the rules of
                 naming conventions for identifiers as shown below:

                                 Examples                                          Commands
                   Creating an empty list                 list1 = []
                   Creating a list with single value      list2 = [56]

                   Creating a list of friends             friends = ["Saisha", "Advika", "Arshia"]
                   Creating a list of marks               marks=[92, 91, 89, 95, 93]

                   Creating a list of students with roll no  students = [21, "Gunjan", 94.5, 34, "Rohit",
                   and percentage (list of mixed values)  91.3]
                   Creating a list within another list    section = ["A", 25, "English", ["B",34], ["C",37],

                                                          56.7]
                   Creating a list with repeated values   L1 = [10] * 5  # L1 will have [10, 10, 10, 10,

                                                          10]
                   Creating  a  list  from  another  sequence  alpha  =  list("hello")  #string  converted  to  a
                   or string using list( ) function       list #output will ['h', 'e', 'l', 'l', 'o']
                   Values input from the user in a list   L1 = list(input("enter numbers :"))


                 Accessing the Elements of a List

                 The elements of a list can be accessed by using its index number starts with 0 (zero). There are two different
                 ways of using the index number:
                    • Positive/Forward Indexing: The index number begins with 0 till length-1 and we refer the elements from left
                   to right.
                    • Negative/Backward Indexing: The index number begins with -1 till -length and we refer the elements from
                   right to left. For example,
                            L1 = ['P', 'Y', 'T', 'H', 'O', 'N']


                                 Forward Indexing      0    1     2    3    4     5
                                                       P    Y     T    H    O     N

                                                      –6    –5   –4   –3    –2   –1       Backward Indexing




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