How Can I Reverse and Iterate Through a Python List?

Reversing and Iterating Backward Through Lists

Often, the need arises to iterate through a list in reverse order. Python offers two approaches to achieve this: getting a reversed copy of the list or iterating directly over the reversed list.

Creating a Reversed List

To obtain a reversed copy of a list, utilize the reversed() function. This function takes the original list as its argument and returns a new list with the elements in reverse order. To save the reversed list, enclose the reversed() output in square brackets:

xs = [0, 10, 20, 40]
reversed_list = list(reversed(xs))  # Note the use of list() to convert the iterator to a list
print(reversed_list)  # Output: [40, 20, 10, 0]

Direct Iteration Over Reversed List

Alternatively, you can iterate directly over the reversed list without creating a new one. This is more efficient and recommended if you only need to access the elements in reverse order:

xs = [0, 10, 20, 40]
for x in reversed(xs):
    print(x)  # Output: 40, 20, 10, 0

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