'''

LISTS

A list is a data structure in Python that is a mutable, or changeable, ordered sequence of elements

Advantage of List over Linked List:

Elements can be accessed through their index value

BigO of Array:

Indexing -----> O(1)

Insert/Delete element at Start -----> O(n)

Insert/Delete element at End -----> O(1)

Insert element at Middle -----> O(n)

'''

# Empty List

list = []

print(f"This is an Empty List: {list}\n")

# List with Elements

list = [1, 2, 3.1, "A"]

print(f"Elements of the list are: {list}\n")

''' Adding elements '''

print("**********Adding Elements**********", end="\n\n")

#add as a single element

list.append(["B", 4])

print("Appended List ", list, end="\n\n")

#add as different elements

list.extend([5, 'E'])

print("Entended List ", list, end="\n\n")

#add element at 1st Index

list.insert(0, 0)

list.insert(5, "F")

print("Inserted Element ", list, end="\n\n")

''' Deleting Elements '''

print("**********Deleting Elements**********", end="\n\n")

#delete element at index 5

del list[5]

print("Deleted element ", list, end="\n\n")

#remove element with value '<val>'

list.remove('E')

print("Removed element ", list, end="\n\n")

#pop element from list at i^th index

a = list.pop(1)

print('Popped Element: ', a, ' List remaining: ', list, end="\n\n")

#empty the list

list.clear()

print("Empty List ", list, end="\n\n")

''' Accessing Elements '''

print("**********Accessing Elements**********", end="\n\n")

list = [1, 2, 3.5, "A", True]

print("This is new list ", list, end="\n\n")

#access elements one by one

print("Accessing all Elements one by one\n")

for element in list:

print(element, end="\n")

#access all elements

print("\nAccessing all elements\n")

print(list, end="\n\n")

#access index i element

print("Element at index=2 is", list[2], end="\n\n")

#access elements from 0 to 1 and exclude 2

print("Elements from index(0 to 1) are ", list[0:2], end="\n\n")

#access elements in reverse

print("Elements in reverse order ", list[::-1], end="\n\n")

'''

Other Functions

len() : returns length of the list.

index() : finds index value of value passed where it has been encountered the first time.

count() : finds count of the value passed to it.

sorted() and sort() : to sort the values of the list.

sorted() has a return type whereas the sort() modifies the original list.

'''

print("**********Other Functions**********", end="\n\n")

list = [1, 2, 3, 10, 20, 50]

#find length of list

print("No of elements in the list ", len(list), end="\n\n")

#find index of element that occurs first

print("Index of element 20 is ", list.index(20), end="\n\n")

#find count of the element

print(f"Elements has been repeated {list.count(10)} time", end="\n\n")

#print sorted list but not change original

print("Sorted list is [AESC] ", sorted(list), end="\n\n")

#sort original list

list.sort(reverse=True)

print("Sorted list is [DESC]", list, end="\n\n")