Python Program to Add two Lists

Write a Python Program to add two Lists (list items) using For Loop and While Loop with a practical example.

Python Program to Add two Lists Example

In this program, we are using For Loop to iterate each element in a given List. Inside the loop, we are adding elements of the first and second lists.

NumList1 = [10, 20, 30]
NumList2 = [15, 25, 35]
total = []
 
for j in range(3):
    total.append( NumList1[j] + NumList2[j])
 
print("\nThe total Sum of Two Lists =  ", total)

In this Python example, NumList1 = [10, 20, 30], NumList2 = [15, 25, 35], total = [] are the Lists

For Loop – First Iteration: for 0 in range(3) – Condition is True
total.append((NumList1[0] + NumList2[0] )
total[0] = 25 (10 + 15)

Second Iteration: for 1 in range(3) – Condition is True
total.append((NumList1[1] + NumList2[1] )
total[1] = 45 (20 + 25)

Third Iteration: for 2 in range(3) – Condition is True
total.append((NumList1[2] + NumList2[0] )
total[2] = 65 (30 + 35)

Fourth Iteration: for 3 in range(3) – Condition is False. So, it exits from For Loop.

Python Program to Add two Lists using For Loop

In this program, we are using two For Loops. They allow users to enter their own number of elements for each list.

NumList1 = []
NumList2 = []
total = []

Number = int(input("Please enter the Total Number of List Elements: "))
print("Please enter the Items of a First List   ")
for i in range(1, Number + 1):
    value = int(input("Please enter the Value of %d Element : " %i))
    NumList1.append(value)

print("Please enter the Items of a Second List   ")
for i in range(1, Number + 1):
    value = int(input("Please enter the Value of %d Element : " %i))
    NumList2.append(value)
    
for j in range(Number):
    total.append( NumList1[j] + NumList2[j])
 
print("\nThe total Sum of Two Lists =  ", total)

Please enter the Total Number of List Elements: 3
Please enter the Items of a First List   
Please enter the Value of 1 Element : 22
Please enter the Value of 2 Element : 33
Please enter the Value of 3 Element : 44
Please enter the Items of a Second List   
Please enter the Value of 1 Element : 55
Please enter the Value of 2 Element : 66
Please enter the Value of 3 Element : 77

The total Sum of Two Lists =   [77, 99, 121]

Python Sum of two Lists using For Loop Example 2

This Python adding two lists is the same as the above. However, we are using one for loop to enter both List1 elements and List2 elements

NumList1 = []
NumList2 = []
total = []

Number = int(input("Please enter the Total Number of List Elements: "))
print("Please enter the Items of a First and Second List   ")
for i in range(1, Number + 1):
    List1value = int(input("Please enter the %d Element of List1 : " %i))
    NumList1.append(List1value)

    List2value = int(input("Please enter the %d Element of List2 : " %i))
    NumList2.append(List2value)
    
for j in range(Number):
    total.append( NumList1[j] + NumList2[j])
 
print("\nThe total Sum of Two Lists =  ", total)

The Sum of two Python lists output

Please enter the Total Number of List Elements: 4
Please enter the Items of a First and Second List   
Please enter the 1 Element of List1 : 10
Please enter the 1 Element of List2 : 35
Please enter the 2 Element of List1 : 20
Please enter the 2 Element of List2 : 45
Please enter the 3 Element of List1 : 50
Please enter the 3 Element of List2 : 75
Please enter the 4 Element of List1 : 90
Please enter the 4 Element of List2 : 135

The total Sum of Two Lists =   [45, 65, 125, 225]

Add two Lists using While Loop

This program for adding two lists elements is the same as the above. We just replaced the For Loop with While loop.

NumList1 = []
NumList2 = []
total = []
i = 1
j = 0

Number = int(input("Please enter the Total Number of List Elements: "))
print("Please enter the Items of a First and Second List   ")
while(i <= Number):
    List1value = int(input("Please enter the %d Element of List1 : " %i))
    NumList1.append(List1value)

    List2value = int(input("Please enter the %d Element of List2 : " %i))
    NumList2.append(List2value)
    i = i + 1
    
while(j < Number):
    total.append( NumList1[j] + NumList2[j])
    j = j + 1
 
print("\nThe total Sum of Two Lists =  ", total)

The Sum of two lists using a while loop output.

Please enter the Total Number of List Elements: 3
Please enter the Items of a First and Second List   
Please enter the 1 Element of List1 : 100
Please enter the 1 Element of List2 : 200
Please enter the 2 Element of List1 : 300
Please enter the 2 Element of List2 : 400
Please enter the 3 Element of List1 : 500
Please enter the 3 Element of List2 : 600

The total Sum of Two Lists =   [300, 700, 1100]