What does the append() function do in a list?

The function append() in Python is specifically designed to add a new element to the end of an existing list. This action modifies the original list by increasing its length by one and placing the new value at the last position. It is a straightforward method commonly used for building lists dynamically, such as when collecting elements in a loop or when items need to be added based on specific conditions.

For instance, if you have a list of integers and you want to add an additional integer, you can simply call list_name.append(new_integer), and this new integer will be added to the end of list_name. The change happens in place, meaning there’s no need to reassign the list to a new variable; the original list reflects the addition.

Understanding this function's role is essential for list manipulation within Python programming, especially when handling dynamic data structures where the size of the list can vary throughout the program's execution.