confused about __str__ vs. __repr__

[Russ P.]

On Dec 18, 1:27 pm, Robert Kern <robert.k... at gmail.com> wrote:
> Mikael Olofsson wrote:
> > Diez B. Roggisch wrote:
> >> Yep. And it's easy enough if you don't care about them being different..
>
> >> def __repr__(self):
> >>     return str(self)
>
> > If I ever wanted __str__ and __repr__ to return the same thing, I would
> > make them equal:
>
> > def __str__(self):
> >     return 'whatever you want'
> > __repr__ = __str__
>
> > That makes it more obvious to me what's going on. As a bonus, it saves
> > one method call for every repr call.
>
> Or just define __repr__(). str() falls back to __repr__() if __str__() is not
> defined.
>
> --
> Robert Kern
>
> "I have come to believe that the whole world is an enigma, a harmless enigma
>   that is made terrible by our own mad attempt to interpret it as though it had
>   an underlying truth."
>    -- Umberto Eco

I learned a while ago to just define __repr__, and let __str__ revert
to it by default. Then, when I print a list for debugging purposes, I
see something useful (as opposed to a type name and an address).

The only reason that I can think of to define __str__ is to get two
different representations. For example, sometimes I need both a one-
line output format and a multi-line option for more clarity or detail.
Then I use __repr__ for the one-liner and __str__ for the multi-liner.