combining lists

[stealth]

Hi there

Can somebody explain why my statement for c also results in a list and not in a set (as the set brackets where used)?
(This is just to understand what is actually happening - I'm not interested in other ways to do it ;-)

a = [5, 5, 1, 45, 3]
b = [3, 8, 92, 5, 45, 6]

c = sorted({x for x in a if x in b})
d = sorted([x for x in a if x in b])

Yoriz write Feb-08-2022, 06:19 AM:
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[deanhystad]

Because sorted takes an iterable argument and returns a list. It doesn't care about the type of the argument as long it is iterable.

From the documents: https://docs.python.org/3/library/functions.html#sorted

sorted(iterable, /, *, key=None, reverse=False)
Return a new sorted list from the items in iterable.

[stealth]

Thanks a lot :-)

[deanhystad]

One other thing. You can't sort a set. By definition a set is an unordered collection.

From the docs: https://docs.python.org/3/tutorial/datas....html#sets

Python also includes a data type for sets. A set is an unordered collection with no duplicate elements. Basic uses include membership testing and eliminating duplicate entries. Set objects also support mathematical operations like union, intersection, difference, and symmetric difference.

If you put sorted values in a set they will not retain their order.