1+ '''
2+ LISTS
3+ A list is a data structure in Python that is a mutable, or changeable, ordered sequence of elements
4+
5+ Advantage of List over Linked List:
6+ Elements can be accessed through their index value
7+
8+ BigO of Array:
9+ Indexing -----> O(1)
10+ Insert/Delete element at Start -----> O(n)
11+ Insert/Delete element at End -----> O(1)
12+ Insert element at Middle -----> O(n)
13+ '''
14+
15+ # Empty List
16+ list = []
17+ print (f"This is an Empty List: { list } \n " )
18+
19+ # List with Elements
20+ list = [1 , 2 , 3.1 , "A" ]
21+ print (f"Elements of the list are: { list } \n " )
22+
23+
24+ ''' Adding elements '''
25+
26+ print ("**********Adding Elements**********" , end = "\n \n " )
27+
28+ #add as a single element
29+ list .append (["B" , 4 ])
30+ print ("Appended List " , list , end = "\n \n " )
31+
32+ #add as different elements
33+ list .extend ([5 , 'E' ])
34+ print ("Entended List " , list , end = "\n \n " )
35+
36+ #add element at 1st Index
37+ list .insert (0 , 0 )
38+ list .insert (5 , "F" )
39+ print ("Inserted Element " , list , end = "\n \n " )
40+
41+
42+ ''' Deleting Elements '''
43+
44+ print ("**********Deleting Elements**********" , end = "\n \n " )
45+ #delete element at index 5
46+ del list [5 ]
47+ print ("Deleted element " , list , end = "\n \n " )
48+
49+ #remove element with value '<val>'
50+ list .remove ('E' )
51+ print ("Removed element " , list , end = "\n \n " )
52+
53+ #pop element from list at i^th index
54+ a = list .pop (1 )
55+ print ('Popped Element: ' , a , ' List remaining: ' , list , end = "\n \n " )
56+
57+ #empty the list
58+ list .clear ()
59+ print ("Empty List " , list , end = "\n \n " )
60+
61+
62+ ''' Accessing Elements '''
63+
64+ print ("**********Accessing Elements**********" , end = "\n \n " )
65+
66+ list = [1 , 2 , 3.5 , "A" , True ]
67+ print ("This is new list " , list , end = "\n \n " )
68+
69+ #access elements one by one
70+ print ("Accessing all Elements one by one\n " )
71+ for element in list :
72+ print (element , end = "\n " )
73+
74+ #access all elements
75+ print ("\n Accessing all elements\n " )
76+ print (list , end = "\n \n " )
77+
78+ #access index i element
79+ print ("Element at index=2 is" , list [2 ], end = "\n \n " )
80+
81+ #access elements from 0 to 1 and exclude 2
82+ print ("Elements from index(0 to 1) are " , list [0 :2 ], end = "\n \n " )
83+
84+ #access elements in reverse
85+ print ("Elements in reverse order " , list [::- 1 ], end = "\n \n " )
86+
87+
88+ '''
89+ Other Functions
90+ len() : returns length of the list.
91+ index() : finds index value of value passed where it has been encountered the first time.
92+ count() : finds count of the value passed to it.
93+ sorted() and sort() : to sort the values of the list.
94+ sorted() has a return type whereas the sort() modifies the original list.
95+ '''
96+
97+ print ("**********Other Functions**********" , end = "\n \n " )
98+
99+ list = [1 , 2 , 3 , 10 , 20 , 50 ]
100+
101+ #find length of list
102+ print ("No of elements in the list " , len (list ), end = "\n \n " )
103+
104+ #find index of element that occurs first
105+ print ("Index of element 20 is " , list .index (20 ), end = "\n \n " )
106+
107+ #find count of the element
108+ print (f"Elements has been repeated { list .count (10 )} , end = "\n \n " )
109+
110+ #print sorted list but not change original
111+ print ("Sorted list is [AESC] " , sorted (list ), end = "\n \n " )
112+
113+ #sort original list
114+ list .sort (reverse = True )
115+ print ("Sorted list is [DESC]" , list , end = "\n \n " )
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