Unit 4 - Lesson 4

37.1.1. Understand the List Operations

(a)l1 = [1, 20, 30, 40] index of l1 starts from 0.

37.1.2. Create and access a List

# write your code here
b = input("data: ").split(',')
print('list:',b)
a=int(input("index: "))
try:
	print('element:',b[a])
except:
	print('invalid')

37.1.3. Write a program to find whether a given element exists in a list or not

x = input("data: ")
y = input("element: ")
print(y in x)

37.1.4. Write a Program to print the first and last elements of a List.

x = input("data: ")
x = x.split(',')
print("first, last elements:", x[0],x[-1])

37.1.5. Understanding List slicing

input_str = input("Enter a list of numbers separated by spaces: ")
# Convert input string into a list of integers
a = []
b= input_str.split(' ')
for i in b:
	if i != " ":
		a.append(int(i))

# Get user inputs start,stop and step for slicing parameters
s = int(input("start index: "))
e = int(input("stop index: "))
v = int(input("step value: "))
# Create a new list using slicing

# Display the sliced list
print("Sliced List:",a[s:e:v])

37.1.6. Write a program to print True as output if the first or last element of a List is 3 otherwise print False

i = input("data: ")
#a = i.split[',']
if i[0] == "3" or i[-1] == "3":
	print(True)
else:
	print(False)

37.1.7. Understanding List Repetition and Concatenation

# write your code here
x = input("data1: ")
y = input("data2: ")
n = int(input("num: "))
x = x.split(",")
print(x*n)
y = y.split(",")
print(y*n)
print("extending list1 with list2:", x+y)

37.1.8. Understanding list comparison

x = input("data1: ")
y = input("data2: ")
l1 = []
l2 = []
x = x.split(',')
y = y.split(',')

print("is equal:",x == y)
print("is not equal:", x != y)

37.1.9. Write a program to print EQUAL if first and last elements of a list are same otherwise print NOT EQUAL

x = input("data: ")
x = x.split(',')
if x[0]==x[-1]:
	print("equal")
else:
	print("not equal")

37.1.10. Understanding Mutability in Lists

# write your code here
x = input("data: ")
x = x.split(",")
print("before updation:", x)
i = int(input("index: "))
if len(x) <= i or -len(x) >=i:
	print("invalid")
else:
	e = input("element: ")
	x[i] = e
	print("after updation:",x)

37.1.11. Write a Program to find the largest of the first and last elements of a List

x = input("data: ")
x = x.split(',')
g = 0
l= []
for i in x:
	l.append(int(i))
print(l)
print("largest among first, last elements:", end=" ")
if x[0]>x[-1]:
	print(x[0])
else:
	print(x[-1])

37.1.12. Understanding List aliasing

# write your code here
list1 = list(input("data: ").split(','))
list2 = list1
print("list1 is list2:",list1 is list2)
print("list2 is list1:",list2 is list1)
i = int(input("index: "))
if len(list1)>=-i and len(list1)>i:
#if i<len(list1) and i>=-len(list1):
	z = input("element: ")
	list1[i] = z
	print("list1 is list2:", list1 is list2)
	print("list2 is list1:", list2 is list1)
else:
	print("enter valid index")

37.1.13. Understanding List Cloning

# write your code here
x = input("Enter a list of numbers separated by spaces: ")
l=[]
for i in x.split(' '):
	l.append(int(i))
print("Original List:", l)
a = l[:]
a[0]=100
print("Cloned List (Slicing):", a)
b= list(l)
b[1] = 200 
print("Cloned List (list() Function):",b)
c = l.copy()
c[2] = 300
print("Cloned List (copy() Method):",c)

37.1.14. Write a program to check whether the first and last elements of two given Lists are same or not

x = input("data1: ").split(",")
y = input("data2: ").split(",")
if (x[0]==y[0]) or (x[-1] == y[-1]):
	print("True")
else:
	print("False")

37.1.15. Understanding and implementing deletion operations on elements in a list.

Warning: Use spaces to indent the functions or it will give Indentation Error

initial_input = input("Enter elements: ")
my_list = initial_input.split()
print("Current List: ", my_list)

def delete_elements_del():
    index = int(input("Enter the index to delete an element: "))
    # Check if the index is valid or not
    try:
        # Delete element at the specified index using 'del'
        del my_list[index]
        print("Updated list: ", my_list)
    except:
        print("Invalid index")

def delete_elements_remove():
    element_to_remove = input("Enter an element to remove: ")
     # Check if element is in the list or not
    if element_to_remove in my_list:
        # Remove the element using 'remove()' method
        my_list.remove(element_to_remove)
        print("Updated list: ", my_list)
    else:
        print("Element not found")

def delete_elements_pop():
    index = int(input("Enter an index to pop an element: "))
    # Check if the index is valid or not
    try:
        # Pop element at the specified index using 'pop()' method
        print("Popped element: ",my_list.pop(index))
        print("Updated list: ", my_list)
    except:
        print("Invalid index")

def clear_list():
   # Clear the list using 'clear()' method
    my_list.clear()
    print("Cleared list: ", my_list)


# Performing operations one by one
delete_elements_del()
delete_elements_remove()
delete_elements_pop()
clear_list()

print("Exiting the program")

37.1.16. Write a program to remove all the duplicates from a List.

# write your code here
x = input("data: ").split(',')
print(x)
l=[]
for i in x:
	if i not in l:
		l.append(i)
print("after removing duplicates:",l)