On Sat, 26 Nov 2005, Diez B. Roggisch wrote: > Tom Anderson wrote: > >> Is this any good? Would it be any use? Should this be added to itertools? > > Whilst not a total itertools-expert myself, I have one little objection > with this: the comparison won't let me know how many items have been > consumed. And I end up with two streams that lack some common prefix > plus one field.
Good point. It would probably only be useful if you didn't need to do anything with the iterators afterwards. One option - which is somewhat icky - would be to encode that in the return value; if n is the number of items read from both iterators, then if the first argument is smaller, the return value is -n, and if the second is smaller, it's n. The trouble is that you couldn't be sure exactly how many items had been read from the larger iterator - it could be n, if the values in the iterators differ, or n+1, if the values were the same but the larger one was longer. > I'm just not sure if there is any usecase for that. I used it in my ordered dictionary implementation; it was a way of comparing two 'virtual' lists that are lazily generated on demand. I'll go away and think about this more. tom -- Gotta treat 'em mean to make 'em scream. -- http://mail.python.org/mailman/listinfo/python-list
