Unary plus operator and __pos__
gerrit at nl.linux.org
Tue Sep 28 09:37:51 CEST 2004
Erik Max Francis wrote:
> Carlos Ribeiro wrote:
> > Now I'm curious about the operator itself. Why is the unary plus
> > operator associated with the __pos__ magic method? I' can't see a
> > relation here, and I could not find much info (although I haven't
> > really looked very hard :-)
> > Anyone knows why is it so?
> Unary plus is __pos__ for positive, unary minus is __neg__ for negative.
> The unary plus operator, I'm sure, is a holdover from C. Since the
> unary plus operator is a no-op for normal numeric values, I would be
> hesitant to use it to mean something else;
The Decimal class does:
>>> n = Decimal((0, (0, ), 'N'))
Traceback (most recent call last):
File "<stdin>", line 1, in ?
File "/usr/local/lib/python2.4/decimal.py", line 863, in __pos__
ans = self._check_nans(context=context)
File "/usr/local/lib/python2.4/decimal.py", line 619, in _check_nans
File "/usr/local/lib/python2.4/decimal.py", line 2243, in _raise_error
raise error, explanation
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