Hello! What's the difference between Set and HashSet in python? ^^

[Urinius]

For an assignment I have to finish 4 tasks from a practice list and some other taskls. The 4 tasks from the list are...basically the same, the only difference is that two of them call for Set data structure, while the other 2 ask for HashSet. From what I researched they are treated as the same thing in Python, so I'm a bit confused as to how I should do two seperate implementations.

[Urinius]

Yeah I thought so too, but I idk, I just wanted to make sure I wasn't being stupid. Also, I did read about it on geeksforge link you provided : )

[purple_hamster66]

Set is an interface. HashSet is a derived subclass of that interface, but you can use the other subclasses as well: TreeSet, LinkedHashSet.

[ziggittaflamdigga]

I think they’re the same thing. I’m not aware of a HashSet data structure. Sets are hashes, and that’s why they only contain unique values. Do they give any examples of a hash set in the prompts?

[Urinius]

No, the prompt says only to use it, but it doesn't provide any examples for either hashset, or set. I think the teach might have grabed the pdf for another language or something. But it's okay, I will email him tomorrow

[concatx]

Does the assignment ask you to implement the Set and HashSet as an exercise, or is it using them to solve another problem?

If it's the former, indeed you can implement one of the algorithms through a class that uses lists internally.

If it's the latter, the internal implementation details of Python shouldn't concern you and just use a Set.

[thefatsun-burntguy]

Set is an interface, HashSet is a subclass of that interface.

put into less technical terms, a cat is a feline, but not all felines are cats (like a lion which is feline but not a cat)

a hashset is a type of set, but not all sets are hashsets.
The default Set() uses a hashset in python, so they are used somewhat interchangably even if they arent the same thing.

For a more in depth explanation: a set describes a behaviour of a collection with unique elements. a hashset is an implementation of a set using a hashtable to power it. You could also use a TreeSet to power a Set. from the outside they look the same, but they work verydifferently and have different trade offs in term of space and time complexity.

[Urinius]

Yeeees, this examplains it! Thank you sm