How to change a module's function - python-2.7

Question

I have a module that I want to import. Lets say its name is module1.py .
There is a function inside this module (F(X,Y)). Here is a part of this module:
def F(X,Y):
S=complex(X,Y)
Fs=2/(pow(S,3))
Rfs=real(Fs)
return Rfs
Sum=F(X,0)/2.
print Sum
I can import this module by:
import module1
But I need to change something in the F function after I import it. For example I want to substitute this function in the module with the old one (I want to change Fs in the F function):
def F(X,Y):
S=complex(X,Y)
Fs=1/(S-1)
Rfs=real(Fs)
return Rfs
Could you please tell me how I can do that in python 2.7?

Answer 1

You can do this by extending Module1. Extending a class allows you to keep all of the previous functions and attributes of the base class but override any that you would like to change.
This example shows that you can call all of the other functions inside of the original Module1 but that when you call the F() function it uses the one from extended class.
Python2.7
Module1.py
class Module1():
def F(self,X,Y):
S=complex(X,Y)
Fs=2/(pow(S,3))
Rfs=real(Fs)
return Rfs
def G(self):
return "function G"
def H(self):
return "function H"
Module1_ext.py
import Module1
class Module1(Module1.Module1):
def F(self,X,Y):
return X*Y;
run.py
from Module1_ext import Module1
mod = Module1()
print(mod.G())
print(mod.H())
print(mod.F(2,3))
Python3+
Module1.py
class Module1():
def F(X,Y):
S=complex(X,Y)
Fs=2/(pow(S,3))
Rfs=real(Fs)
return Rfs
def G():
return "function G"
def H():
return "function H"
Module1_ext.py
import Module1
class Module1(Module1.Module1):
def F(X,Y):
return X*Y;
run.py
from Module1_ext import Module1
print(Module1.G())
print(Module1.H())
print(Module1.F(2,3))

Answer 2

Finally I figured it out by myself. This is how I solved the issue:
First we need to rewrite the module in this form:
module1.py
from numpy import *
M = 11
SU = zeros(M + 2)
C = zeros(M + 1)
C[0] = 1
for k in range(1, M + 1):
C[k] = (M - (k - 1)) * C[k - 1] / k
# T=input("TIME=")
class BB:
def F(self, fnRf):
T=1
A = 19.1
U = exp(A / 2.) / T
X = A / (2. * T)
H = pi / T
Ntr = 15
Sum = fnRf(X, 0) / 2.
for N in range(1, Ntr + 1):
Y = N * H
Sum += (-1) ** N * fnRf(X, Y)
SU[0] = Sum
for K in range(1, M + 2):
N = Ntr + K
Y = N * H
SU[K] = SU[K - 1] + (-1) ** N * fnRf(X, Y)
Avgsu = 0.
Avgsu1 = 0.
for J in range(M + 1):
Avgsu += C[J] * SU[J]
Avgsu1 += C[J] * SU[J + 1]
Fun = U * Avgsu / 2048
Fun1 = U * Avgsu1 / 2048
print Fun1
We can import this module like this:
from module1 import *
def fnRf(X, Y):
S = complex(X, Y)
Fs = 1. / (S-1)
Rfs = real(Fs)
return Rfs
ss=BB()
ss.F(fnRf)
This way we are flexible to define the function (in the module). Now it works perfectly. I hope it was helpful.