Bartc wrote: ^^^^^ Please fix. > On 06/11/2015 02:33, wa...@travelsky.com wrote: >> As you can see in the attachment, why i can modify "math.pi"? >> (in "mathmodule.c" "pi" is a "static const double") > > Python isn't C. > > Your attachment isn't visible, but it can be demonstrated easily: > > 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. -- PointedEars Twitter: @PointedEars2 Please do not cc me. / Bitte keine Kopien per E-Mail. -- https://mail.python.org/mailman/listinfo/python-list
