How to Compare Two Lists and Find At Least One Equal Element in Python?

To compare two lists and find if there is at least one equal element in Python, you can use the any() function in combination with a list comprehension or a loop. Here’s an example:

Using the any() function with list comprehension:

list1 = [1, 2, 3, 4, 5]
list2 = [6, 7, 8, 9, 10]

# Check if at least one element is equal using list comprehension and any()
has_equal_element = any(item in list1 for item in list2)

if has_equal_element:
    print("There is at least one equal element")
else:
    print("There are no equal elements")

Using a loop:

list1 = [1, 2, 3, 4, 5]
list2 = [6, 7, 5, 9, 10]

# Check if at least one element is equal using a loop
has_equal_element = False
for item in list2:
    if item in list1:
        has_equal_element = True
        break

if has_equal_element:
    print("There is at least one equal element")
else:
    print("There are no equal elements")

In both examples, we have two lists, list1 and list2, and we want to determine if there is at least one element that is present in both lists.

The first example uses a list comprehension to iterate over each item in list2 and checks if it is present in list1. The any() function returns True if at least one element matches the condition, and False otherwise.

The second example uses a loop to iterate over each item in list2. Inside the loop, it checks if the item is present in list1. If a match is found, the has_equal_element variable is set to True, and the loop is terminated using break.

After the loop or the list comprehension, we check the value of has_equal_element to determine if there is at least one equal element between the two lists. The corresponding message is then printed.

In the second example, you can modify the code to perform additional actions when an equal element is found, such as printing the specific element or its index.

By using the any() function with a list comprehension or a loop, you can compare two lists and determine if there is at least one equal element in Python.