On Tue, Mar 2, 2021 at 2:16 PM Chris Angelico <ros...@gmail.com> wrote: > > On Tue, Mar 2, 2021 at 5:51 AM Alan Gauld via Python-list > <python-list@python.org> wrote: > > > > On 28/02/2021 00:17, Cameron Simpson wrote: > > > > > BUT... It also has a __iter__ value, which like any Box iterates over > > > the subboxes. For MDAT that is implemented like this: > > > > > > def __iter__(self): > > > yield from () > > > > Sorry, a bit OT but I'm curious. I haven't seen > > this before: > > > > yield from () > > > > What is it doing? > > What do the () represent in this context? > > > > It's yielding all the elements in an empty tuple. Which is none of > them, meaning that - for this simple example - iterating over the > object will produce zero results.
I discovered something new (to me) yesterday. Was writing a unit test for generator function and I found that none of the function got executed at all until I iterated on the return value. It was blowing my mind as I was debugging the test and had a BP set in the first line of the function but it was not hit when I called the function. -- https://mail.python.org/mailman/listinfo/python-list
