C3 Linearization and Python MRO(Method Resolution Order)

bebound@gmail.com (KK) — Sat, 14 Mar 2020 17:37:00 +0800

Python supports multiple inheritance, its class can be derived from more than one base classes. If the specified attribute or methods was not found in current class, how to decide the search sequence from superclasses? In simple scenario, we know left-to right, bottom to up. But when the inheritance hierarchy become complicated, it’s not easy to answer by intuition.

For instance, what’s search sequence of class M?

class X:pass
class Y: pass
class Z:pass
class A(X,Y):pass
class B(Y,Z):pass
class M(B,A,Z):pass

The answer is: M, B, A, X, Y, Z, object

MRO on KK's Blog (fromkk)

C3 Linearization and Python MRO(Method Resolution Order)