Slicing reversal (default)
Input
reverse_list([1, 2, 3])
Output
[3, 2, 1]
Default behavior returns a new list reversed using slicing.
Full lesson preview
Reverse a list in-place and by slicing
Return a reversed list either by creating a new reversed copy or by reversing the original list in-place.
Python practice8 minLists & TuplesBeginnerLast updated March 17, 2026
Problem statement
Write a function reverse_list(lst, in_place=False). When in_place is False (the default), return a new list that is the reversed copy of lst using slicing. When in_place is True, reverse lst in-place and return the same list object (now reversed). The function should work for lists containing any types.
Task
Implement a function that can return a reversed copy of a list or reverse the list in-place based on a flag.
Examples
Input format
A list as the first argument and an optional boolean in_place flag.
Output format
A list that is the reversed version of the input list (either a new list or the original mutated list).
Constraints
Do not import external libraries. When in_place is True, mutate the provided list; when False, do not change the original list.
Samples
Sample 1
Input
reverse_list([1, 2, 3], True)
Output
[3, 2, 1]
The original list is reversed in-place and returned.