Jakob Bowyer wrote:
There is that but from a math point of view the syntax a * b does make sence. Its slightly clearer and makes more sense to people from outside of a programming background.
I realise that the consensus is that the lack of associativity is a fatal problem with a Cartesian product operator, but there are at least two other issues I haven't seen. (1) "Using * for set product makes sense to mathematicians" -- maybe so, but those mathematicians already have to learn to use | instead of ∪ (union) and & instead of ∩ (intersection), so learning to use itertools.product() for Cartesian product is not a major burden for them. (2) Cartesian product is potentially very expensive. The Cartesian product of a moderate-sized set and another moderate-sized set could turn out to be a HUGE set. This is not a fatal objection, since other operations in Python are potentially expensive: alist*10000000 but at least it looks expensive. You're multiplying by a big number, of course you're going to require a lot of memory. But set multiplication can very easily creep up on you: aset*bset will have size len(aset)*len(bset) which may be huge even if neither set on their own is. Better to keep it as a lazy iterator rather than try to generate a potentially huge set in one go. -- Steven