How Do I Efficiently Access and Modify the Last Element of a Python List?

Getting the Last Element of a List: Python Syntax and Best Practices

Accessing the last element of a list in Python can be achieved through various methods. Two common options include:

alist[-1]

and

alist[len(alist) - 1]

However, the preferred approach for simplicity and conciseness is the first method:

some_list[-1]

This syntax has added versatility, allowing you to retrieve elements from various positions:

• some_list[-1] gets the last element.
• some_list[-2] gets the second to last element.
• some_list[-len(some_list)] retrieves the first element.

Furthermore, list elements can be modified using the negative index syntax:

>>> some_list = [1, 2, 3]
>>> some_list[-1] = 5 # Set the last element
>>> some_list[-2] = 3 # Set the second to last element
>>> some_list
[1, 3, 5]

It's important to note that accessing list items by index raises an IndexError if the specified item does not exist. Consequently, using some_list[-1] on an empty list, for instance, will result in an exception.

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