Problem: B changes, as you can see when you run the short program below. So does the original matrix, although I don’t care about that.
Question: Why does the list B change when I don’t work on it? I want to understand this.
Question #2: A solution would be to convert the list B into a tuple and then reconvert the tuple back into a list after the new matrix has been mutated and insert it, but I still want to understand why a list would change when I’m haven’t done anything to it.
Here’s a small program that reproduces the problem. When B changes depends upon the value you set for ‘e’
import random
A = [[1,1,1,1,1], [2,2,2,2,2],[3,3,3,3,3],[4,4,4,4,4]]
e = 2
B = A[e]
Columns = 4
Rows = 4
NewMatrix = A
MutationRate = .9999 #Mutation of NewMatrix
s = 0
while s<Rows:
print "B is", B
h=0
while h<Columns: #mutate individual members
x=random.random()
if x<=MutationRate:
NewMatrix[s][h] = abs(NewMatrix[s][h] - 9)
if h == Columns - 1: break
h += 1
if s ==Rows -1: break
s += 1
print 'B is', B
print A
print "*******"
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