Python advanced Three: Object-oriented Basics

Initialize Instance properties: Enter the keyword information attr= ' attr1 ' can be used with kw.iteritems ()

class Person (object):    def __init__ (self,name,gender,birth,**kw):        self.name=name        Self.gender=gender        Self.birth=birth for        k,v in Kw.iteritems ():            setattr (self,k,v) xiaoming = person (' Xiao Ming ', ' Male ', ' 1990-1-1 ', job= ' Student ') print Xiaoming.nameprint xiaoming.job

Access restrictions: Variables that begin with a double underscore cannot be accessed externally

class Person (object):    def __init__ (self, Name, score):        self.name=name        self.__score=scorep = person (' Bob ') , P.__score) Print P.nameprint

Define class Properties: Properties that are directly bound to a class do not need to create an instance and can be accessed directly with the class name (class properties and instance property conflicts: First look for an instance attribute assignment or reference and then the Class property)

class Person (object):    count = 0    def __init__ (self,name):        self.name=name        person.count=person.count+ 1P1 = person (' Bob ') print PERSON.COUNTP2 = person (' Alice ') print PERSON.COUNTP3 = person (' Tim ') print Person.count

Define instance methods: an instance is a function defined in a class, and its first argument is always self, pointing to the instance itself that invokes the method, and the other arguments are exactly the same as a normal function

class Person (object):    def __init__ (self, Name, score):        self.name=name        self.__score=score    def get_ Grade (self):        return self.__scorep1 = person (' Bob ', ' all ') P2 = person (' Alice ', ' + ') P3 = person (' Tim ', ') print P1.get_grad E () print p2.get_grade () print P3.get_grade ()

Add a method to an instance dynamically: the instance method that we define in class is actually a property, which is actually a function object:

Import Typesdef Fn_get_grade (self):    if Self.score >=:        return ' A '    if Self.score >=:        return ' B '    return ' C ' class Person (object):    def __init__ (self, Name, score):        self.name = name        Self.score = SCOREP1 = person (' Bob ', p1.get_grade) = types. Methodtype (Fn_get_grade, p1, person)  #将fn_get_grade绑定到P1实例print p1.get_grade () # = + AP2 = person (' Alice ', 65) Print P2.get_grade () # error:attributeerror: ' Person ' object with no attribute ' Get_grade ' # because P2 instance is not bound Get_grade

Class method: Before defining a method, add @classmethod to the class method class method cannot get the instance information class method input to pass in a class object

class Person (object):    __count = 0    @classmethod    def how_many (CK):        return ck.__count    def __init__ ( Self,name):        self.name=name        person.__count=person.__count+1print person.how_many () p1 = person (' Bob ') print Person.how_many ()

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Python advanced Three: Object-oriented Basics