Cant access variable from anywhere

[deanhystad]

private variable implies a class. Python has classes. Python classes are just like C# classes. Here is a Python class based on your original post.

class SomeClass:
    def __init__(self, m, s, t, y, z=0):
        self.m = m
        self.s = s
        self.t = t
        self.y = y
        self._z = z

    @property
    def z(self):
        f = (self.m - 5) / (self.m - self._z)
        sm = self.s / f
        fi = sm + self.t
        self._z = fi / self.y
        return self._z

    @z.setter
    def z(self, value):
        self._z = value

thing = SomeClass(1, 2, 3, 4)
print(thing.z, thing.z, thing.z)

thing.y = 2
thing.z = 0
print(thing.z, thing.z, thing.z)

Output:
0.625 0.703125 0.712890625
1.25 1.5625 1.640625

As you can see from the output. z changes value each time it is accessed. Also demonstrated is how you can change attributes of the object (values used in the equations) from outside the class.