[issue15815] Add numerator to ZeroDivisionError messages
Ezio Melotti added the comment: Terry, do you still think that adding the numerator would be useful? -- ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue15815 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue15815] Add numerator to ZeroDivisionError messages
Mark Dickinson added the comment: I'll add my -1 to this; I don't really see the use. -- ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue15815 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue15815] Add numerator to ZeroDivisionError messages
Terry J. Reedy added the comment: Not enough, at present, to leave this open. -- resolution: - rejected status: open - closed ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue15815 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue15815] Add numerator to ZeroDivisionError messages
Ezio Melotti added the comment: I'm not sure this is really useful. Once I know that I divided by zero and I know where the division is, I don't really care what the numerator is. Knowing the exact type of the denominator (0, 0.0, 0j) doesn't sound too useful as well -- unless you somehow manage to get the wrong type and a 0-value at the same time. On a side note, I don't like ZeroDivisionError: integer division or modulo of 3 by 0 too much, but I would prefer ZeroDivisionError: integer division (or modulo) by zero over ZeroDivisionError: integer division or modulo by zero IIRC the reason why both division and modulo are included in the message is because the error is created in a piece of code that is shared by both operations. -- ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue15815 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue15815] Add numerator to ZeroDivisionError messages
New submission from Terry J. Reedy:
I propose that we add 'of ' to all ZeroDivisionError messagesso it is less
necessary to use a debugger to add print statements to recover the information
currently tossed away. (I also propose to change denominator from 'zero' to
'0', '0.0', '0+0j', as appropriate.)
3//0
...
ZeroDivisionError: integer division or modulo by zero
# augment to
ZeroDivisionError: integer division or modulo of 3 by 0
Similarly for
3 / 0
ZeroDivisionError: division by zero
# perhaps this should be 'true division of 3 by 0'
3.0 / 0.0
ZeroDivisionError: float division by zero
(3+3j) / (0+0j)
ZeroDivisionError: complex division by zero
In #7482 it was proposed to make float and complex messages same as int message
by adding 'or modulo'. I an not sure why not to do that, or if it was just
deferred.
Fractions currently print the numerator as part of an invalid numerator / 0
result from *either* construction or division.
from fractions import Fraction as F
F(3, 0)
Traceback (most recent call last):
File pyshell#20, line 1, in module
F(3, 0)
File C:\Programs\Python33\lib\fractions.py, line 167, in __new__
raise ZeroDivisionError('Fraction(%s, 0)' % numerator)
ZeroDivisionError: Fraction(3, 0)
# Here, 'Fraction(3, 0)' is invalid input.
F(3, 1) / F(0, 1)
Traceback (most recent call last):
File pyshell#19, line 1, in module
F(3, 1) / F(0, 1)
File C:\Programs\Python33\lib\fractions.py, line 367, in forward
return monomorphic_operator(a, b)
File C:\Programs\Python33\lib\fractions.py, line 417, in _div
a.denominator * b.numerator)
File C:\Programs\Python33\lib\fractions.py, line 167, in __new__
raise ZeroDivisionError('Fraction(%s, 0)' % numerator)
ZeroDivisionError: Fraction(3, 0)
# Here, 'Fraction(3, 0)' is invalid output.
I found this confusing until I worked out the dual meaning. I think
ZeroDevisionError: invalid Fraction(3, 0) from construction or division
might be a bit clearer.
I have not looked at decimals.
--
components: Interpreter Core
messages: 169410
nosy: ezio.melotti, mark.dickinson, terry.reedy
priority: normal
severity: normal
stage: needs patch
status: open
title: Add numerator to ZeroDivisionError messages
type: enhancement
versions: Python 3.4
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[issue15815] Add numerator to ZeroDivisionError messages
Antoine Pitrou added the comment: What would be the point? Usually you should find out why the denominator is zero, not what the numerator's value is. -- nosy: +pitrou ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue15815 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue15815] Add numerator to ZeroDivisionError messages
Terry J. Reedy added the comment: In case the value of the numerator helps find out why the denominator is 0. The example given by Mike Graham on python-ideas, Verbose traceback formatting was def f(a): x = a * 4 y = a - 4 return x / y -- ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue15815 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue15815] Add numerator to ZeroDivisionError messages
Antoine Pitrou added the comment: In case the value of the numerator helps find out why the denominator is 0. The example given by Mike Graham on python-ideas, Verbose traceback formatting was def f(a): x = a * 4 y = a - 4 return x / y Well, in this case y == 0 iff a == 4. I don't see how the numerator helps at all. (and besides, it's a rather silly artificial example) -- ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue15815 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
