Python super() Function
Python Built-in FunctionsDescription
super()The function is used to call a method of the parent class (superclass).
super()It is used to solve multiple inheritance problems. Calling a parent class method directly with the class name is fine for single inheritance, but with multiple inheritance, it involves various issues such as method resolution order (MRO), repeated calls (diamond inheritance), etc.
MRO is the method resolution order table of a class, which is actually the order table used when inheriting parent class methods.
Syntax
The following is the syntax of the super() method:
super(type[, object-or-type])
Parameters
- type -- class.
- object-or-type -- class, usually self
One difference between Python3.x and Python2.x is: Python 3 can directly usesuper().xxxinstead ofsuper(Class, self).xxx :
Python3.x Example:
class A:
def add(self, x):
y = x+1
print(y)
class B(A):
def add(self, x):
super().add(x)
b = B()
b.add(2) # 3
Python2.x Example:
#!/usr/bin/python
# -*- coding: UTF-8 -*-
class A(object): # Python2.x remember to inherit object
def add(self, x):
y = x+1
print(y)
class B(A):
def add(self, x):
super(B, self).add(x)
b = B()
b.add(2) # 3
Return Value
None.
Example
The following shows an example of using the super function:
Example
#!/usr/bin/python
# -*- coding: UTF-8 -*-
class FooParent(object):
def __init__(self):
self.parent = 'I\'m the parent.'
print ('Parent')
def bar(self,message):
print ("%s from Parent" % message)
class FooChild(FooParent):
def __init__(self):
# super(FooChild,self) first finds the parent class of FooChild (that is class FooParent), then converts the object of class FooChild to an object of class FooParent
super(FooChild,self).__init__()
print ('Child')
def bar(self,message):
super(FooChild, self).bar(message)
print ('Child bar fuction')
print (self.parent)
if __name__ == '__main__':
fooChild = FooChild()
fooChild.bar('HelloWorld')
Execution result:
Parent Child HelloWorld from Parent Child bar fuction I'm the parent.Other Extensions