Python Advanced---Object-oriented third projectile (Advanced article)

Some methods in Python objects

First, __str__

Class Teacher:
def __init__ (self,name,age):
Self.name=name
Self.age=age
Self.courses=[]

def teach (self):
Print ('%s teach '%self.name)

def __str__ (self):
Return ' <name:%s age:%s> '% (self.name,self.age)

Class Course:
def __init__ (self,name,price,period):
Self.name=name
Self.price=price
Self.period=period
def __str__ (self):
Return ' name:%s price:%s period:%s '% (self.name,self.price,self.period)

# egon=teacher (' Egon ', 18)
# print (Egon) #egon. __str__ ()
# print (Egon) #egon. __str__ ()

Ii. usage of __del__

Import time
# class Foo:
# def __init__ (self,x):
# self.x=x
# print (' Connect MySQL ') #conn =abcdef (' 192.168.1.10 ', 3306)
#
# def __del__ (self):
# ' Do some cleanup operations related to this object '
# # Conn.close ()
# # File.close ()
# print (' ====> ')
# F=foo (10)
# del F #f. __del__ ()
# Time.sleep (3)
# print (' main program ')

Third, item usage

Methods such as dic[' a '] can be implemented

# l=[' A ', ' B ', ' C ')
# dic={' a ': 1}
#
# print (l[1])
# Print (dic[' a '])

Class Foo:
def __init__ (self,name,age,sex):
Self.name=name
Self.age=age
Self.sex=sex
def __getitem__ (self, item):
# Print (Self,item,type (item))
# return GetAttr (Self,item)
return Self.__dict__[item]
def __setitem__ (self, Key, value):
# setattr (Self,key,value)
Self.__dict__[key]=value

def __delitem__ (self, key):
# delattr (Self,key)
Self.__dict__.pop (Key)

def __len__ (self):
Return 10
F=foo (' Egon ', ' Male ')
# print (f.name) #f [' name ']
# print (f.age) #f [' Age ']
# print (f.sex) #f [' Sex ']

# print (f[' name ')

# f[' name ']= ' EGON_NB '
# Print (f.__dict__)
# del f[' name ']
# Print (f.__dict__)

Print (Len (f))

Iv. Isinstance and Issubclass

Isinstance (obj,cls) checks if obj is an object of class CLS

Class Foo (object):
Pass

obj = Foo ()

Isinstance (obj, Foo)
Issubclass (sub, super) check if the sub class is a derived class of super class

Class Foo (object):
Pass

Class Bar (Foo):
Pass

Issubclass (Bar, Foo)

V. Reflection

Class Teacher:
# school= ' Oldboy '
# def __init__ (self,name,age):
# Self.name=name
# Self.age=age
#
# def teach (self):
# print ('%s teach '%self.name)

# Print (Teacher.school)
# Print (teacher.__dict__[' school ')

# Print (hasattr (Teacher, ' School '))

# Print (GetAttr (Teacher, ' School '))
# Print (GetAttr (Teacher, ' solasdf ', None))

# teacher.x=123
# setattr (Teacher, ' X ', 123)
# Print (teacher.x)

# delattr (Teacher, ' school ')
# Print (Teacher.school)

#对象
# t=teacher (' Egon ', 18)
# print (hasattr (t, ' name ')) #判断对象是否有name属性("in string mode" )

# print (GetAttr (t, ' name ')) #获取对象的name属性("in string mode" )

# setattr (t, ' sex ', ' Male ') #修改对象的sex属性 ("In the Way of strings")
# print (GetAttr (t, ' sex '))
#
# Print (t.__dict__)
# delattr (t, ' name ')
# Print (t.__dict__)

# T.teach ()
# Print (T.school)

# print (GetAttr (t, ' teach '))
# print (GetAttr (t, ' School '))
# t.school= ' Hahahahahahahahahhahahahahahhahahahahahahh '
# Print (t.__dict__)

Python Advanced---Object-oriented third projectile (Advanced article)