Question

I have this (example) code:

init()

class A:
    foo = bar()

    def __init__(self):
        print(A.foo)

The problem is, the function bar() refuses to work unless init() has been called first. What is a nice Pythonesque solution for this problem?

---

In my specific situation init() is third-party and can not be adapted and is called in a different file than A is defined.

Answer 1

Like this?

class A:
    foo = None
    def __init__(self):
        if A.foo is None:
             A.foo = bar()
        print(A.foo)

You could also move the if statement to A.__new__() if you are not sure A.__init__() will be called (e.g. when unpickling an A object before explicitly calling its constructor).