Why all the __double_underscored_vars__?

[David Cournapeau]

On Sat, Aug 8, 2009 at 9:11 PM, kj<no.email at please.post> wrote:
> In <mailman.4446.1249683227.8015.python-list at python.org> Chris Rebert <clp2 at rebertia.com> writes:
>
>>The double-underscores indicate that the Python interpreter itself
>>usually is the caller of the method, and as such some level of "magic"
>>may be associated with it. Other languages have you do the equivalent
>>of `def +():` or `def operator +()` to override an operator, the
>>keyword or symbol serving a similar warning that "here be magic".
>
> In this case, then I hope that some of these __items__ get demoted
> to a more mundane level, so that the notion of "magic" doesn't get
> trivialized by everyday idioms like:
>
> if __name__ == '__main__':
>    # etc
>
> There are a few in this category...  I figure that they are cases
> of "atavistic magic".
>
> I bring this up because I find it quite difficult to explain to my
> students (who are complete newcomers to programming) all the
> __underscored__ stuff that even rank noobs like them have to deal
> with.  (Trust me, to most of them your reply to my post would be
> as clear as mud.)

Maybe your students do not need to know about it, at least at the
beginning ? I heavily use python, and do not use the underscore
methods so much most of the time, except for __init__,

cheers,

David