Multiple inheritance
- Python course
- Intermediate
- Lesson 10/116
- 4 min
Learn multiple inheritance and MRO.
Multiple inheritance
Multiple inheritance is when a class inherits from more than one parent. Parents are separated by commas in parentheses.
Example: class C(A, B): pass. Here C inherits from both A and B. Methods of both parents are available on a C instance. If a same-name method exists, the MRO order decides.
MRO order
MRO (Method Resolution Order) is the order in which Python searches parents. In multiple inheritance it goes left to right. You can see the order with C.mro().
Example: for class C(A, B) the MRO is [C, A, B, object]. So c.hello() is searched in C first, then A, then B. In diamond inheritance C3 linearization produces a consistent order.
Practice Multiple inheritance C class
Define class A; add def hello(self): and in the body write print("A"). Define class B; add def hello(self): and in the body write print("B"). Then define class C(A, B): pass. Create an instance with c = C() and call c.hello().
Starter code
# Define the A, B and C classesSample solution
# Define the A, B and C classes
class A:
def hello(self):
print("A")
class B:
def hello(self):
print("B")
class C(A, B):
pass
c = C()
c.hello()Expected output
A
Questions and answers
Review the lesson questions together with their answers. To test yourself, solve the lesson interactively.
1 Which is a multiple inheritance definition?
- class C: pass
- class C(A, B): pass Correct answer
- class C extends A, B: pass
- class C(A): pass
Explanation: Two parents separated by a comma show multiple inheritance.
2 Complete the multiple inheritance definition
class C(A, ____):
passclass C(A, B):
passExplanation: The second parent is added with a comma.
3 Match the multiple inheritance concepts
| Term | Meaning |
|---|---|
class C(A, B) |
Multiple inheritance |
C.mro() |
Resolution order |
A, B |
Comma parents |