how to overload sqrt in a module?
Robert Kern
robert.kern at gmail.com
Fri Mar 3 04:39:05 CET 2006
Michael McNeil Forbes wrote:
> Here is one fairly ugly solution:
>
> module_g.py
> -----------
> def g(x,math):
> return math.sqrt(x)
>
>
>>>>import math, cmath, module_g
>>>>module_g.g(2,math)
>
> 1.4142135623730951
>
>>>>module_g.g(-2,cmath)
>
> 1.4142135623730951j
>
> I am sure there is a better way of doing this that makes use of the
> type of the argument (Dynamical scoping would solve the
> problem but we don't want to go there...). Note that the following
> function would work fine
>
> def f(x):
> return abs(x)
>
> because of the special member __abs__ attached to the type. There is no
> corresponding member for sqrt, sin etc.
>
> What is the "proper" pythonic way to do this?
Use the appropriate library which already implements the features you want.
In [8]: class A(object):
...: def __init__(self, x):
...: self.x = x
...: def sqrt(self):
...: return 2*self.x
...:
...:
In [9]: a = A(10)
In [10]: import numpy
In [11]: numpy.sqrt(a)
Out[11]: 20
In [12]: numpy.sqrt(10)
Out[12]: 3.1622776601683795
In [13]: numpy.sqrt(10j)
Out[13]: (2.2360679774997898+2.2360679774997898j)
--
Robert Kern
robert.kern at gmail.com
"In the fields of hell where the grass grows high
Are the graves of dreams allowed to die."
-- Richard Harter
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