Python Program to Find Intersection of Two Lists

Here is a Python program to find the intersection of two lists:

list1 = [1, 2, 3, 4, 5]
list2 = [4, 5, 6, 7, 8]

intersection = list(set(list1) & set(list2))

print("Intersection of list1 and list2:", intersection)

In this program, we first define two lists list1 and list2. Then, we use the built-in set function to convert each list into a set, which removes any duplicates in the list. We then use the & operator to find the intersection of the two sets. Finally, we convert the resulting set back to a list using the list function and assign it to the variable intersection.

We then print out the intersection of the two lists using the print statement. When we run the program, the output will be:

Intersection of list1 and list2: [4, 5]

This means that the intersection of list1 and list2 contains the values 4 and 5, which are the common elements in both lists.

Method – 1: Using for loop:

Yes, we can also find the intersection of two lists using a for loop in Python. Here is an example program that uses a for loop to find the intersection of two lists:

list1 = [1, 2, 3, 4, 5]
list2 = [4, 5, 6, 7, 8]

intersection = []

for element in list1:
    if element in list2:
        intersection.append(element)

print("Intersection of list1 and list2:", intersection)

In this program, we first define two lists list1 and list2. We then create an empty list called intersection to store the common elements between the two lists.

We use a for loop to iterate through each element in list1. Inside the loop, we use an if statement to check whether the current element is also in list2. If it is, we append the element to the intersection list.

Finally, we print out the intersection list using the print statement. When we run the program, the output will be:

Intersection of list1 and list2: [4, 5]

This means that the intersection of list1 and list2 contains the values 4 and 5, which are the common elements in both lists.

Method – 2: Convert List to Set:

Yes, another way to find the intersection of two lists in Python is by converting them into sets and using the intersection method. Here’s an example program that uses this method:

list1 = [1, 2, 3, 4, 5]
list2 = [4, 5, 6, 7, 8]

set1 = set(list1)
set2 = set(list2)

intersection = list(set1.intersection(set2))

print("Intersection of list1 and list2:", intersection)

In this program, we first define two lists list1 and list2. We then convert them into sets using the built-in set function and assign them to the variables set1 and set2.

We then use the intersection method to find the common elements between the two sets. This method returns a new set that contains only the elements that are common to both sets.

Finally, we convert the resulting set back to a list using the list function and assign it to the variable intersection. We then print out the intersection list using the print statement. When we run the program, the output will be:

Intersection of list1 and list2: [4, 5]

This means that the intersection of list1 and list2 contains the values 4 and 5, which are the common elements in both lists.