On Thu, Oct 5, 2017 at 1:20 PM, Steve D'Aprano <steve+pyt...@pearwood.info> wrote: > On Thu, 5 Oct 2017 09:42 am, Stefan Ram wrote: > >> Steve D'Aprano <steve+pyt...@pearwood.info> writes: >>>>So, "bottom-up" in this case means: iterators should be >>>>taught before for-loops. >>>Why? >> >> The syntax for is (from memory): >> >> for <variable> in <expression>: <suite> >> >> . As an example, I might show: >> >> for i in range( 3 ): ... >> >> . This raises the question: >> >> "What is the value of »range( 3 )«?". > > That's easy: in Python 2, it is a list [0, 1, 2]. In Python 3, it is a range > object, a lazily calculated list-like object.
Even easier: in any version of Python, it is the series of numbers 0, 1, 2. You can go a rather long way without worrying about what "series" actually means at the concrete level. It's a thing you can iterate over, and that's all that matters to 99%+ of range() usage. ChrisA -- https://mail.python.org/mailman/listinfo/python-list
