Of course! In Python, there isn't a built-in function called lastIndexOf() like you might find in JavaScript or Java. However, achieving the same result is straightforward using a couple of different methods.

Here are the best ways to find the last index of an element in a list, from the most common to the most robust.

The Most Common Method: Using list.index() with reversed()

This is the most "Pythonic" and readable way for most use cases. The idea is to reverse the list, find the first occurrence of the element in that reversed list, and then calculate the index from the original list.

The formula is: len(list) - 1 - reversed_list.index(element)

Here's how you implement it:

# Our list of numbers
my_list = [10, 20, 30, 40, 50, 30, 60]
# The element we want to find
element_to_find = 30
# Find the last index
try:
    # Reverse the list and find the first index of the element
    reversed_index = my_list[::-1].index(element_to_find)
    # Calculate the index in the original list
    last_index = len(my_list) - 1 - reversed_index
    print(f"The list is: {my_list}")
    print(f"The last index of {element_to_find} is: {last_index}")
except ValueError:
    # This block runs if the element is not in the list
    print(f"Element {element_to_find} not found in the list.")
# --- Example with an element not in the list ---
element_not_found = 99
try:
    reversed_index = my_list[::-1].index(element_not_found)
    last_index = len(my_list) - 1 - reversed_index
    print(f"The last index of {element_not_found} is: {last_index}")
except ValueError:
    print(f"Element {element_not_found} not found in the list.") # This will be printed

Output:

The list is: [10, 20, 30, 40, 50, 30, 60]
The last index of 30 is: 5
Element 99 not found in the list.

Why this works:

1. my_list[::-1] creates a reversed copy of the list ([60, 30, 50, 40, 30, 20, 10]).
2. .index(30) on this reversed list finds the first occurrence, which is at index 1.
3. We calculate the original index: len(my_list) is 7. So, 7 - 1 - 1 = 5.

The Manual Loop (The "From the End" Approach)

This method is very explicit and easy to understand, especially for beginners. You simply loop through the list from the end towards the beginning and return the index as soon as you find the element.

def find_last_index(data, element):
    """
    Finds the last index of an element in a list by iterating from the end.
    Returns -1 if the element is not found.
    """
    for i in range(len(data) - 1, -1, -1):
        if data[i] == element:
            return i  # Found it, return the index immediately
    return -1 # If the loop finishes, the element was not found
# --- Example Usage ---
my_list = [10, 20, 30, 40, 50, 30, 60]
# Find the last index of 30
last_index = find_last_index(my_list, 30)
print(f"The last index of 30 is: {last_index}") # Output: 5
# Find the last index of 99
last_index_99 = find_last_index(my_list, 99)
print(f"The last index of 99 is: {last_index_99}") # Output: -1

Pros:

• Very clear logic.
• You don't need to handle a try...except block if you choose to return -1 for "not found" (a common convention).

Cons:

• Slightly more verbose than the reversed() method.

The Most Robust Method: Creating a Reusable Function

For clean and reusable code, it's best to wrap your preferred logic in a function. This function should handle both the "found" and "not found" cases gracefully.

Here is a robust function using the reversed() approach.

def last_index_of(lst, item):
    """
    Returns the last index of an item in a list.
    Returns -1 if the item is not found.
    """
    try:
        # Use the reversed slicing trick
        return len(lst) - 1 - lst[::-1].index(item)
    except ValueError:
        # This exception is raised if item is not in the list
        return -1
# --- Example Usage ---
my_list = ['apple', 'banana', 'orange', 'apple', 'grape']
print(f"List: {my_list}")
# Find last index of 'apple'
print(f"Last index of 'apple': {last_index_of(my_list, 'apple')}") # Output: 3
# Find last index of 'banana'
print(f"Last index of 'banana': {last_index_of(my_list, 'banana')}") # Output: 1
# Find last index of 'kiwi' (not in list)
print(f"Last index of 'kiwi': {last_index_of(my_list, 'kiwi')}") # Output: -1

This function is clean, handles errors, and can be easily imported and used in any other part of your project.

Summary and Recommendation