Question

我试图理解django中基于类的视图概念。在此之前，我应该知道函数调用和return语句。我想知道它在下面提到的代码。我知道即将调用父类函数。应该归还什么任何人都可以用例子解释这个概念。提前谢谢。

class Foo(Bar):
  def baz(self, arg):
    return super(Foo, self).baz(arg)

Answer 1

我用例子解释这个。

我正在创建两个类，其中一个是inheriting来自其他类。

class Parent(object):

    def implicit(self):
        print "PARENT implicit()"

class Child(Parent):
    pass

dad = Parent()
son = Child()

>>>dad.implicit()
>>>son.implicit()
"PARENT implicit()"
"PARENT implicit()"

这会创建一个名为class的{{1}}，但表示在其中定义并不新鲜。相反，Child将inherit Parent的所有行为。{/ p>

现在下一个例子

class Parent(object):

    def override(self):
        print "PARENT override()"

class Child(Parent):

    def override(self):
        print "CHILD override()"

dad = Parent()
son = Child()

>>>dad.override()
>>>son.override()
"PARENT override()"
"CHILD override()"

即使Child inherits来自Parent，Child.override条消息的所有行为，因为son是instance Child而且Child通过定义自己的版本

来覆盖该功能

现在下一个例子，

class Parent(object):

    def altered(self):
        print "PARENT altered()"

class Child(Parent):

    def altered(self):
        print "CHILD, BEFORE PARENT altered()"
        super(Child, self).altered()
        print "CHILD, AFTER PARENT altered()"

dad = Parent()
son = Child()

>>>dad.altered()
>>>son.altered()
"PARENT altered()"
"CHILD, BEFORE PARENT altered()"
"PARENT altered()"
"CHILD, AFTER PARENT altered()"

在这里，我们可以找到super(Child, self).altered()，它知道inheritance并且会获得Parent class。（不关心覆盖）

希望这有帮助

更新。。在python3

super().altered()可以代替super(Child, self).altered()

了解更多http://learnpythonthehardway.org/book/ex44.html

Answer 2

class Foo(Bar):#here Bar is your super class, you inherit  super class methods 
  def baz(self, arg):#this class method 
    return super(Foo, self).baz(arg)# here super is mentioned as  super class of Foo .baz(arg) is you call the super user method baz(arg)

所以你需要创建像

这样的超类

class BAR(object):
   def baz(self,arg):
       c=10+20
       return c

两个基类的简单示例

class bar(object):
  def baz(self, arg):
    print"this is bar class" 

class bar1(object):
  def baz1(self,arg):
    print "this is bar1 class"         
class Foo(bar,bar1):
  def baz(self, arg):
    super(Foo, self).baz1(arg)  
    super(Foo, self).baz(arg)

a=Foo()
a.baz("hai")

django中基于类的视图

2 个答案: