On 2021-11-05 at 06:28:34 +1100, Chris Angelico <ros...@gmail.com> wrote:
> On Fri, Nov 5, 2021 at 6:23 AM <2qdxy4rzwzuui...@potatochowder.com> wrote: > > > > On 2021-11-04 at 14:36:48 -0400, > > David Lowry-Duda <da...@lowryduda.com> wrote: > > > > > > x_increment, y_increment = (scale * i for i in srcpages.xobj_box[2:]) > > > > > > > > (scale * i for i in srcpages.xobj_box[2:]) is a generator, a single > > > > object, it should not be possible to unpack it into 2 variables. > > > > > > If you know the exact number of values in the generator, you can do > > > this. Here is an oversimplified example. > > > > > > l = [0, 1, 2, 3, 4, 5] > > > a, b = (elem * 10 for elem in l[:4]) > > > print(a, b) # prints 40 50 > > > > > > This is very fragile code and I would recommend against using it. > > > > How is that any more fragile than any other operation that destructs (or > > doesn't) a tuple? > > > > The only part that's fragile, in my opinion, is (from the initial > post) that it's using removal syntax to slice off some, which is > fragile against the original input length: > > x_increment, y_increment = (scale * i for i in srcpages.xobj_box[2:]) > > But since it says "box", I would start by assuming that it has four > elements. (They might be x1,y1,x2,y2 or x,y,w,h but it'll almost > always be four.) So it's not TOO fragile, when working with boxes, but > it is a little less clear that thing[2:] will always give exactly two > results. I won't disagree that most boxes are going to be described by four elements, in which case slicing off the first two *should* leave two more (presumably x_increment and y_increment). So if you're saying that all that's missing is a description of srcpages.xobj_box, then I agree. :-) But such is life on a mailing list where posters don't always give their questions the context they deserve. -- https://mail.python.org/mailman/listinfo/python-list
