John Clark wrote: > Hello Tutors, > > I am having trouble wrapping my mind around nested list > comprehensions and am hoping that someone can either verify my > thinking or provide insight as to what I am doing wrong. > > If I weren't trying to use list comprehensions, I would > code this as: > > result = [] > for eachObject in C1: > for eachSubObject in eachObject.m(): > result.append(eachSubObject) > > what I think I have come up with is: > > result = [eachSubObject for eachObject in C1 for eachSubObject in > eachObject.m()]
This is the correct equivalent. > If this _is_ the correct syntax, this reads very awkwardly to me, and > my initial reaction to this is that it should be expressed as: > > result = [eachSubObject for eachSubObject in eachObject.m() for eachObject in > C1] FWIW I think it is awkward too. > However, in my testing, this doesn't appear to work. If somone has a > way of reading the nested list comprehension syntax that makes sense, > I would appreciate it if you would share it. I don't know if it makes sense, but the way I think of it is that list comps don't change the order of the 'for x in y' part of the loop, they just move the expression of what to add to the list to the beginning of the code. Kent _______________________________________________ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
