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Groups > comp.lang.python > #109502
| From | Peter Otten <__peter__@web.de> |
|---|---|
| Newsgroups | comp.lang.python |
| Subject | Re: Operator precedence problem |
| Date | 2016-06-05 09:35 +0200 |
| Organization | None |
| Message-ID | <mailman.5.1465112166.2306.python-list@python.org> (permalink) |
| References | <816c651a-d0ae-4e23-a5b2-72a8f7398468@googlegroups.com> <nj0kol$ps$1@ger.gmane.org> |
ICT Ezy wrote:
>>>> 2 ** 3 ** 2
> Answer is 512
> Why not 64?
> Order is right-left or left-right?
** is a special case:
"""
The power operator ** binds less tightly than an arithmetic or bitwise unary
operator on its right, that is, 2**-1 is 0.5.
"""
https://docs.python.org/3.5/reference/expressions.html#id21
Here's a little demo:
$ cat arithdemo.py
class A:
def __init__(self, value):
self.value = str(value)
def __add__(self, other):
return self._op(other, "+")
def __pow__(self, other):
return self._op(other, "**")
def __repr__(self):
return self.value
def _op(self, other, op):
return A("({} {} {})".format(self.value, op, other.value))
$ python3 -i arithdemo.py
>>> A(1) + A(2) + A(3)
((1 + 2) + 3)
>>> A(1) ** A(2) ** A(3)
(1 ** (2 ** 3))
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Operator precedence problem ICT Ezy <ictezy@gmail.com> - 2016-06-04 23:53 -0700
Re: Operator precedence problem Peter Otten <__peter__@web.de> - 2016-06-05 09:35 +0200
Re: Operator precedence problem ICT Ezy <ictezy@gmail.com> - 2016-06-05 08:05 -0700
Re: Operator precedence problem Uri Even-Chen <uri@speedy.net> - 2016-06-05 19:05 +0300
Re: Operator precedence problem ICT Ezy <ictezy@gmail.com> - 2016-06-05 20:24 -0700
Re: Operator precedence problem Lawrence D’Oliveiro <lawrencedo99@gmail.com> - 2016-06-05 22:46 -0700
Re: Operator precedence problem Random832 <random832@fastmail.com> - 2016-06-06 09:57 -0400
Re: Operator precedence problem Marko Rauhamaa <marko@pacujo.net> - 2016-06-06 17:22 +0300
Re: Operator precedence problem Random832 <random832@fastmail.com> - 2016-06-06 10:35 -0400
Re: Operator precedence problem Marko Rauhamaa <marko@pacujo.net> - 2016-06-06 17:55 +0300
Re: Operator precedence problem Jon Ribbens <jon+usenet@unequivocal.co.uk> - 2016-06-06 15:03 +0000
Re: Operator precedence problem Marko Rauhamaa <marko@pacujo.net> - 2016-06-06 18:22 +0300
Re: Operator precedence problem Jon Ribbens <jon+usenet@unequivocal.co.uk> - 2016-06-06 15:27 +0000
Re: Operator precedence problem Chris Angelico <rosuav@gmail.com> - 2016-06-07 01:57 +1000
Re: Operator precedence problem Jon Ribbens <jon+usenet@unequivocal.co.uk> - 2016-06-06 16:05 +0000
Re: Operator precedence problem Chris Angelico <rosuav@gmail.com> - 2016-06-07 02:21 +1000
Re: Operator precedence problem Jon Ribbens <jon+usenet@unequivocal.co.uk> - 2016-06-06 17:02 +0000
Re: Operator precedence problem Grant Edwards <grant.b.edwards@gmail.com> - 2016-06-06 16:51 +0000
Re: Operator precedence problem Peter Otten <__peter__@web.de> - 2016-06-06 18:38 +0200
Re: Operator precedence problem Steven D'Aprano <steve@pearwood.info> - 2016-06-07 03:07 +1000
Re: Operator precedence problem Random832 <random832@fastmail.com> - 2016-06-06 14:44 -0400
Re: Operator precedence problem Marko Rauhamaa <marko@pacujo.net> - 2016-06-06 21:49 +0300
Re: Operator precedence problem MRAB <python@mrabarnett.plus.com> - 2016-06-06 20:17 +0100
Re: Operator precedence problem Gregory Ewing <greg.ewing@canterbury.ac.nz> - 2016-06-07 11:27 +1200
Re: Operator precedence problem Rustom Mody <rustompmody@gmail.com> - 2016-06-06 10:14 -0700
Re: Operator precedence problem Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-06-06 21:09 +0100
Re: Operator precedence problem Michael Torrie <torriem@gmail.com> - 2016-06-05 17:47 -0600
Re: Operator precedence problem ICT Ezy <ictezy@gmail.com> - 2016-06-05 20:23 -0700
Re: Operator precedence problem Chris Angelico <rosuav@gmail.com> - 2016-06-06 02:24 +1000
Re: Operator precedence problem Peter Pearson <pkpearson@nowhere.invalid> - 2016-06-06 16:58 +0000
Re: Operator precedence problem Gregory Ewing <greg.ewing@canterbury.ac.nz> - 2016-06-07 11:21 +1200
Re: Operator precedence problem Random832 <random832@fastmail.com> - 2016-06-05 13:19 -0400
Re: Operator precedence problem ICT Ezy <ictezy@gmail.com> - 2016-06-05 20:23 -0700
Re: Operator precedence problem Gary Herron <gherron@digipen.edu> - 2016-06-05 00:04 -0700
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