CODEWITHSUNDEEP
pythonpython-3.x
gdogg371
gdogg371

Reputation: 4122

Call a class in file B from file A and then reference file B variables in file A

I have two .py files. The first contains a class. The second imports that class and it's function, then attempts to reference variables within that function locally as so:

File B:

class master_test():
    def __init__(self):
        pass

    def func_one(self, var1, var2, var3):
        if var1 == 1:
            print('first')
        else:
            print('second')
        if var2 == 2:
            print('first')
        else:
            print('second')
        if var3 == 3:
            print('first')
        else:
            print('second')
        return var1, var2, var3

File A:

import sys
sys.path.append('G:\Python36\Test\Folder_1')
from Test1 import *

test_var = master_test()
test_var.func_one(6,7,8)

temp = var1
print(temp)

However, when I run file A, I get the following error:

Traceback (most recent call last):
  File "G:/Python36/Test/Master.py", line 8, in <module>
    temp = var1
NameError: name 'var1' is not defined

What am I doing wrong?

Thanks

Upvotes: 0

Views: 49

Answers (2)

Tom Lubenow
Tom Lubenow

Reputation: 1161

var1 is not a module-level variable in Test1.py. It belongs to a function func_one of a class master_test. A class is not an object, a class is a template to create objects. You could have multiple master_test objects.

Imagine you had this code:

from Test1 import master_test

test_var1 = master_test()
test_var2 = master_test()

test_var1.func_one(6,7,8)
test_var2.func_one(2,3,4)

Now if you wanted to reference var1, which one do you even want? The one from test_var1 or from test_var2? You need to re-think how you're passing around data. The correct way to pass data back from functions is to use a return statement.

temp, _, _ = test_var1.func_one(6, 7, 8)

This will set temp equal to var1, which is 6.

Upvotes: 0

Barmar
Barmar

Reputation: 780851

var1 is a local variable, you can't access it outside the function.

But it returns it, so you can assign the result.

x, y, z = test_var.func_one(6, 7, 8)
print(x)

Upvotes: 3

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