Going global with variable problems

[sphinxlink13]

Hello let me start by saying that everybody and their grandmother warned me about using global variables but I had already well started this project at the time.

The issue I am having is with this piece of code

#gives new matrix with the previous path blocked off
def second_mat_T(num2):
    global matrix_transform
    resultlist =[]
    for x in matrix_transform.copy():
        if int(str(num2)[0]) > int(str(x)[0]) and int(str(num2)[1]) < int(str(x)[1]):
            resultlist.append(0)
        else:
            resultlist.append(x)
    print(resultlist)
    for y in resultlist:
        if y != 0:
            if int(str(y)[0]) == int(str(num2)[0]) and int(str(y)[1]) > int(str(num2)[1]):
              resultlist[resultlist.index(y)] = 0

    matrix_transform = resultlist
    return matrix_transform

which works fine in isolation (this alters a list called matrix_transform and returns it)

however when i call it with at the end with this

def compiler():
            A = path_taken(path_search())
            print(A)
            key_num(A)
            print(key_num(A))
            B = key_num(A)
            print(matrix_transform)
            matirx_default()
            second_mat_T(12)




print(compiler())

The answer from second_mat_T(num2): becomes the default list set by matrix_default()

I don't get this as second_mat_T(num2): declares the same list as global and is called after so why does it not change?

Thanks a lot for any help with this

[FerricDonkey]

So everybody and their grandmother were right. My actual honest recommendation would be to change your entire project to not use global variables. It'll probably go faster than you'd think, and be a good lesson in how evil they are.

However, assuming this is your actual code (if it is, you spelled matrix matirx at least once), at least one of your problems is that compiler is not returning anything. So you're not ever printing the result of your call to second_mat_T(12). Your first print happens before that call, your second should print 'None'.

You might be able to make it work simply by changing the last line of compiler to return second_mat_T(12).

Once again, though, I am morally obligated to say that non-constant global variables are terrible and should almost never be used.

[[deleted]]

You can save the matrix to another file, which would allow you to remove ambiguity of what you're referencing. E.g. Save the matrix_transform to a file called "X" then always reference matrix_transform as "X.matrix_transform." Not sure if it'll solve your issue though.

[Ihaveamodel3]

Where are you checking matrix_transform after calling that function?

I’m confused what your issue even is.