I send you a question because I have a problem on python and I don't understand why. I created a function "mut1" to change the number inside a list (with a probability to 1/2) either in adding 1 or subtracting 1, except for 0 and 9:
def mut1 (m):
i=np.random.randint(1,3)
j=np.random.randint(1,3)
if i==1:
if 0<m<9:
if j==1:
m=m+1
elif j==2:
m=m-1
elif m==0:
if j==1:
m=1
if j==2:
m=9
elif m==9:
if j==1:
m=0
if j==2:
m=8
print m
mut1 function well, for example, if I create a list P1:
>>>p1=np.array(range(8),int).reshape((4, 2))
After that, I apply "mut1" at a number (here 3) in the list p1
>>>mut1(p1[1,1])
Hovewer if I write:
>>> p1[1,1]=mut1(p1[1,1])
I have a message error:
Traceback (most recent call last): File "<stdin>", line 1, in <module> TypeError: long() argument must be a string or a number, not 'NoneType'
That happens because you have to make your mut1 return an numpy.int64 type of result. So I tried with the following modified code of yours and worked.
>>> import numpy as np
>>> import random
>>>
>>> def mut1 (m):
... i=np.random.randint(1,3)
... j=np.random.randint(1,3)
... if i==1:
... if 0<m<9:
... if j==1:
... m=m+1
... elif j==2:
... m=m-1
... elif m==0:
... if j==1:
... m=1
... if j==2:
... m=9
... elif m==9:
... if j==1:
... m=0
... if j==2:
... m=8
... return np.int64(m)
...
>>> p1=np.array(range(8),int).reshape((4, 2))
>>> mut1(p1[1,1])
2
>>> p1[1,1]=mut1(p1[1,1])
>>>
So the only thing you need to change is to replace print m with return np.int64(m) and then should work!
You will easily understand why this happened with the following kind of debugging code:
>>> type(p1[1,1])
<type 'numpy.int64'>
>>> type(mut1(p1[1,1]))
<type 'NoneType'>