OrderedSet

Python Morsels Exercise

Set-like object that maintains insertion-order of items

3 bonuses 8 hints 15 solutions 279 users solved 24 reviews

I'd like you to make an OrderedSet class. This class should work like a set, but it should also maintain the insertion order of the items added to it (unlike Python's built-in set which is unordered).

>>> ordered_words = ['these', 'are', 'words', 'in', 'an', 'order']
>>> print(*set(ordered_words))
an words in these are order
>>> print(*OrderedSet(ordered_words))
these are words in an order
>>> print(*OrderedSet(['repeated', 'words', 'are', 'not', 'repeated']))
repeated words are not

This set should be relatively memory efficient and containment checks should be relatively time efficient:

>>> words = OrderedSet(['hello', 'hello', 'how', 'are', 'you'])
>>> len(words)
4
>>> 'hello' in words
True

Initially you don't have to worry about allowing sets to be modified after they've been made. Just focus on getting len and the in operator.

Bonus 1


This is just a preview of the problem statement.

This exercise includes 3 bonuses and 8 hint links.

To solve this exercise, sign in to your Python Morsels account.

A learning habit for experienced Pythonistas

Profile picture of Trey

My name is Trey Hunner and I hold Python trainings for teams. I've spent countless hours refining my most interesting Python exercises into Python Morsels, a Python skill-building platform for folks who already know Python. Python Morsels is design to help you deepen your Python skills every week.

Sign up for Python Morsels to access this exercise and many more.

Join Python Morsels ✨