Check Iterable Equality the Right Way

This is a really useful tip from Trey. Need to check whether two Python lists have equal items? Just use the == operator!

list1 == list2

Using == on lists will check the contents of each list to make sure they contain equivalent items. What if you have two iterables that might not be lists? You could convert them both to lists:

list(iterable1) == list(iterable2)

But if performance is an issue (whether CPU time or memory), you might want to do this instead:

all(
    a == b
    for a, b in zip(iterable1, iterable2, strict=True)
)

That strict=True argument only works on Python 3.10 and above. If you leave out strict=True, zip will stop comparing once it reaches the end of the shortest iterable (meaning if one iterable is a prefix of the other, they’ll be seen as equal). For more on this topic, watch my new screencast on checking the equality of different iterables.