[Python-ideas] Default return values to int and float

[Ron Adam]

On Wed, 2011-10-05 at 08:06 -0700, Ethan Furman wrote:
> Ron Adam wrote:
> > I really don't like the '-1' for a not found case. They just get in the
> > way.
> > 
> > If len(s) was the not found case, you get a value that can be used in a
> > slice without first checking the index, or catching an exception.
> 
> So every time we want to know if s.find() failed, we have to compare to 
> len(s)?

I think probably None would have been better than -1. At least then you
will get an error if you try to use it as an index.

The problem with len(s) as a failure, is when you consider rfind(). It
should return 1 before the beginning, which coincidentally it does, but
you still can't use it as a slice index because it will give you 1 from
the end instead.

So until we find a another way to do negative sequence indexing. It
won't quite work as nice as it should.

Cheers,
   Ron