On 11/6/2015 5:26 PM, Thomas 'PointedEars' Lahn wrote:
Bartc wrote:
import math
math.pi=0
print (math.pi)
In Python, presumably 'pi' is just another variable, and variables can
be written to.
“pi” is the name of an attribute of the module object referred to by “math”.
(Perhaps math.pi would be better off as a function.)
Perhaps not. Calling a function includes an overhead that one does not want
in already costly floating-point calculations.
In my opinion, mathematical constants should be implemented as constants
(non-overwritable, non-deletable, throwing exceptions when attempting to do
either) but apparently the authors of math.py disagree.
One of multiple discussions of the 'constants' idea.
bugs.python.org/issue1465406
It is mostly about speed.
--
Terry Jan Reedy
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