List Methods

reverse()

Reverse the elements of the list in place.

list.reverse()

list.reverse() reverses the order of elements directly inside the list without creating a new copy.

Because it operates in place, it uses O(1) extra memory.

Returns

None — the list is reversed in place.

Run it and change it

countdown = [1, 2, 3, 4, 5]
countdown.reverse()
print(countdown)

reverse() vs reversed(): list.reverse() modifies the list in place and returns None. The built-in reversed(list) returns an iterator leaving the original list unchanged.