Python面向对象编程中关于类和方法的学习笔记

class Person(object):
  pass

class Person(object):
  eyes = 2
  mouth = 1

class Person(object):
  eyes = 2
  mouth = 1
  name = mink

class Person(object):
  eyes = 2
  mouth = 1
  
  def __init__(self, name):
    self.name = name 

me = Person('mink')

class Person(object):
  eyes = 2
  mouth = 1

  def __init__(self, name)
    self.name = name 

  def jineng(self, txt):
    print "%s %s" % (self.name, txt)

me = Person('mink')
me.jineng("我不受重力影响, 我会飞")

class Animal(object):
  name = 'lili'
  age = 1

cat = Animal()
print cat.name, cat.age   # print 'lili' 1

# 显示内容是一样的
print cat.name, cat.age
print Animal.name, Animal.age
给Animal类添加一个方法(函数)

class Animal(object):
  name = 'lili'
  age = 1

  def edit(self, name, age):
    self.name = name
    self.age = age

cat = Animal()
cat.edit('rol', 2)

print cat.name, cat.age     # print 'rol' 2
print Animal.name, Animal.age  # print 'lili' 1

# 我们修改一下这个函数
def edit(self, name, age):
  name = name
  self.age = age

cat = Animal()
cat.edit('rol', 2)

print cat.name, cat.age     # pirnt 'rol' 2
print Animal.name, cat.age   # print 'lili' 1

# 再一次修改edit
@classmethod
def edit(cls, name, age):
  cls.name = name
  cls.age = age

cat = Animal()
cat.edit('rol', 2)

print cat.name, cat.age     # print 'rol' 2
print Animal.name, Animal.age  # print 'rol' 2

class Animal(object):
  name = 'lili'
  age = 1

  def __init__(self, name, age):
    self.name = name
    self.age = age
  ...

cat = Animal('kuku', 4)
cat.edit('rol', 2)

print cat.name, cat.age     # print 'kuku' 4
print Animal.name, Animal.age  # print 'rol' 2

# 添加staticmethod
@staticmethod
def say_name(name=None):
  if not name:
    name = self.name
  print 'my name is %s.' % name

cat = Animal('kaka', 3)
cat.say_name()        
# 运行的话会报 NameError: global name 'self' is not defined  
# 那是不是没给他添加self字段, 所以没找到
def say_name(self, name=None):
  ...

cat.say_name()
# TypeError: say_name() takes at least 1 argument(0 given), 显示缺少参数

# 我们修改一下代码
# 先创建一个实例的方法, 他使用类的staticmethod

@staticmethod
def say_name(name):
  print 'my name is %s.' % name

def say(self):
  self.say_name(self.name)
  
@classmethod
def _say(cls):
  cls.say_name(cls.name)

cat = Animal('kaka', 3)
cat.say()
cat._say()