Not using the __init__ constructor?

That is, is there a declaration option (variable initialization) that will be instance fields without using a constructor?

    2 answers 2

     class A: b = 1 def c(self, z): print(self) return z a = A() print(ab) Ac = c print(ac(2)) ad = c print(ad(a, 3)) ae = 4 print(ae) class D(dict): pass d = D(name='my_name', num=3) print(d)

      There are several options. In all the examples below, I will show how to assign a field "x" equal to 1 to a class object.

      First: Declare a "bare" instance of the class, and with the ready-made instance, use your hands to set the necessary attributes.

       class A: pass a = A() ax = 1

      Second: Use the new special method.

       class A: def __new__(cls): obj = super(A, cls).__new__(cls) obj.x = 1 return obj

      Third: write the initialization method, and run it either by hand after creating the instance, or automatically from new.

       class A: def my_init(self): self.x = 1 a = A() a.my_init()

      This is just what offhand comes to mind. I suspect, then you can come up with similar options.

      But the correct way is to use init.