For review: PEP 308 - If-then-else expression

[Paul Moore]

David Eppstein <eppstein at ics.uci.edu> writes:

> As far as I can remember, the last time I wanted to use that construct, 
> I couldn't, because b was false.  Hah!  Found it:
>
>         if i < 0:
>             col = None
>         else:
>             col = cols[i]
>
> Here cols[i] is a string, and I didn't want to assume that it is always 
> nonempty, so the and-or construct doesn't work.  I think this would be a 
> good candidate for a one-liner:
>
>         col = cols[i] if i >= 0 else None

As Andrew Dalke already pointed out, this is a good example in that
most of the standard workarounds don't work.

But I don't like the look of the one-liner, if I read it in someone
else's code. I also don't think I'd naturally think to write it that
way in my own code.

It's shorter, which means that if I had a lot of these, my function
would be hard to read because it was too big. But I think I'd split
the function up before that happened.

Dunno, it's a good example, but I *still* don't feel convinced of the
need.

Paul.
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