Teaching the "range" function in Python 3

[Chris Angelico]

On Fri, Jun 30, 2017 at 6:57 AM, Irv Kalb <Irv at furrypants.com> wrote:
> I am wondering if other teachers have run into this.  Is this a real problem?  If so, is there any other way of explaining the concept without getting into the underlying details of how a generator works?  Do you think it would be helpful to use the words "sequence of numbers" rather than talking about a list here - or would that be even more confusing to students?
>

The easiest way is to use the word "collection" for things you iterate
over (rather than the concrete term "list"). So you can loop through
(or iterate over) a collection of explicitly given numbers:

for number in [12, 93, -45.5, 90]:

or you can loop through a range of numbers:

for number in range(10):

or you can loop through any number of other things:

for file in os.scandir("."):

They're all collections. I'd also use this as a great opportunity to
talk about naming conventions - a collection is named in the plural
("things") whereas individual items are named in the singular
("thing") - which means that it's very common to have a loop that
looks like this:

for thing in things:
for file in files:
for num in numbers:
for key in keyring:

That rule should help people keep things straight, without being
bothered by the difference between lists, ranges, and dictionary
views.

ChrisA