Python basics-class

Python basics-class

All object-oriented languages have classes.

Today, I will share with you a little bit about classes in Python, focusing on comparison with classes in C ++.

In C ++, the parent class is called superclass in Python)

Create class

class Person: def setName(self, name):   self.name = name def getName(self):   return self.name def greet(self):   print "Hello, world! I'm %s. " % self.name

This keyword in C ++, called self in Python
It seems that the self keyword is more vivid.

Binds a feature to a common function.

>>>class Class:     def method(self):       print 'I have a self!'>>>def function():     print "I don't...">>>instance = Class()>>>instance.method()I have a self!>>>instance.method = function>>>instance.method()I don't...

Private
Python does not have a private keyword. Whether it is a method change or a feature, add a Double underline before the name:

class Secretive:  def __inaccessible(self):    print 'Bet you can't see me...'

Specify the superclass
That is, the parent class and inheritance in C ++. The colon is not used here, but the superclass are written in the brackets behind the subclass:

class Filter:  def init(self):    self.blocked = []class SPAMFilter(Filter):  def init(self):    self.blocked = ['SPAM']

Check inheritance
As far as I know, there is no direct method in C ++ to determine whether two classes have parent-child relationships.
There are built-in methods in Python. The issubclass function:

>>>issubclass(SPAMFilter, Filter)true>>>issubclass(Filter, SPAMFilter)false

The only thing to note is that the first parameter is a subclass and the second parameter is a superclass.

Check whether an object is an instance of a class.
Isinstance method. The first parameter is the instance, and the second parameter is the class name.

Multiple superclasses
That is, the multiple inheritance mentioned in C ++, that is, several classes are written in parentheses, separated by commas.