All permutations from 2 lists

[Larry Martell]

On Tue, Mar 1, 2022 at 7:21 PM <2QdxY4RzWzUUiLuE at potatochowder.com> wrote:
>
> On 2022-03-01 at 19:12:10 -0500,
> Larry Martell <larry.martell at gmail.com> wrote:
>
> > If I have 2 lists, e.g.:
> >
> > os = ["Linux","Windows"]
> > region = ["us-east-1", "us-east-2"]
> >
> > How can I get a list of tuples with all possible permutations?
> >
> > So for this example I'd want:
> >
> > [("Linux", "us-east-1"), ("Linux", "us-east-2"), ("Windows",
> > "us-east-1"), "Windows", "us-east-2')]
> >
> > The lists can be different lengths or can be 0 length. Tried a few
> > different things with itertools but have not got just what I need.
>
> [(o, r) for o in os for r in region]

This does not work if region = []. I wrote in my question that either
list could be empty.