Python reversed() Function: Usage and Examples

A timeline displays recent events before older ones.

What You Need to Understand

reversed(sequence) returns an iterator that walks a reversible sequence backward without modifying it. Convert the iterator to a list when a concrete collection is required.

When to Use It

A timeline displays recent events before older ones.

Step-by-Step Python Example

events = ["opened", "edited", "saved"]
for event in reversed(events):
    print(event)
print(events)

How the Example Works

The loop visits saved, edited and opened in that order; the original list order remains unchanged.

Example Output

saved
edited
opened
['opened', 'edited', 'saved']
[3, 2, 1]

A Second Example

Compare this smaller variation with the main example, then experiment with your own values.

numbers = [1, 2, 3]
print(list(reversed(numbers)))

Important Behavior and Edge Cases

Not every iterable supports reversed() directly. list.reverse() modifies a list in place, while slicing with [::-1] creates a copy.

Try It Yourself

Print an event list backward and then forward.

Common Beginner Mistakes

Not every iterable supports reversed() directly. list.reverse() modifies a list in place, while slicing with [::-1] creates a copy.
Overlooking how an iterable is consumed, how element positions are chosen, or whether a function creates a new list.

Key Takeaways

reversed(sequence) returns an iterator that walks a reversible sequence backward without modifying it.
The loop visits saved, edited and opened in that order; the original list order remains unchanged.
Not every iterable supports reversed() directly.