Make a Playlist Feel Like a List

Medium ⏱ 12 min 56% acceptance ★★★★★ 4.5

Wrap a list of song titles in a Playlist class implementing __len__ and __getitem__ so len(p), p[0], negative indexing and even for song in p all work — implementing __getitem__ alone is enough to make an object iterable.

Examples

Example 1

Input

p = Playlist(['a', 'b']); (len(p), p[-1])

Output

(2, 'b')

Explanation

Both dunders delegate to the wrapped list.

Constraints

Store the songs list internally.
Delegate, do not reimplement indexing math.

Topics

OOP__len__ and __getitem__

Companies

SpotifyNetflixApple

Hints

Hint 1

return self._songs[index] handles negatives free of charge.

Hint 2

Iteration falls back to __getitem__ with 0, 1, 2, …

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