Method, attribute, iterator, and pyhon Attribute Generator in pyhon

Method, attribute, iterator, and pyhon Attribute Generator in pyhon

Constructor:

The constructor is similar to the initialization method named init used in the previous example.

When an object is created, the constructor is called immediately.

>>> class FooBar:    def __init__(self):        self.somevar=42        >>> f=FooBar()>>> f.somevar42>>> class fOSyntaxError: invalid syntax>>> class FooBar():    def __init__(self,value=42):        self.somevar=value        >>> f=FooBar('This is a constructor argument')>>> f.somevar'This is a constructor argument'

Override general methods and special constructor Methods

>>> Class Bird: def _ init _ (self): self. hungry = True def eat (self): if self. hungry: print 'aaaah... 'self. hungry = False else: print 'no, thanks! '>>> B = Bird () >>> B. eat () Aaaah... >>> B. eat () No, thanks! >>> Class SongBird (Bird): def _ init _ (self): Bird. _ init _ (self) # Call the superclass constructor self. sound = 'squawk! 'Def sing (self): print self. sound >>> sb = SongBird () >>> sb. sing () Squawk! >>> Sb. eat () Aaaah...> sb. eat () No, thanks!

Super Function

Super (SongBird, self)

For more information, see: http://www.cnblogs.com/lovemo1314/archive/2011/05/03/2035005.html

>>> __metaclass__=type>>> class Bird:    def __init__(self):        self.hungry=True    def eat(self):        if self.hungry:            print 'Aaaah...'            self.hungry=False        else:            print 'No,thinks!'            >>> class SongBird(Bird):    def __init__(self):        super(SongBird,self).__init__()        self.sound='Squawk!'    def sing(self):        print self.sound        >>> n=SongBird()>>> n.sing()Squawk!>>> n.eat()Aaaah...>>> n.eat()No,thinks!

Attribute

The features defined by the accessors are called attributes.

>>> Class Rectangle: def _ init _ (self): self. width = 0 # feature self. height = 0 # feature def setSize (self, size): # Use the accessor method to change the feature self. width, self. height = size def getSize (self): # return self. width, self. height >>> r = Rectangle () >>> r. width = 10 >>> r. height = 5 >>> r. getSize () (10, 5) >>> r. setSize (150,100) >>> r. width150

Property Function

>>> __metaclass__=type>>> class Rectangle:    def __init__(self):        self.width=0        self.height=0    def setSize(self,size):        self.width,self.height=size    def getSize(self):        return self.width,self.height    size=property(getSize,setSize)    >>> r=Rectangle()>>> r.width=10>>> r.height=5>>> r.size(10, 5)>>> r.size=150,100>>> r.width150

Iterator

The iterator has the next

 

>>> class Fibs:    def __init__(self):        self.a=0        self.b=1    def next(self):        self.a,self.b=self.b,self.a+self.b        return self.a    def __iter__(self):        return self    >>> fibs=Fibs()>>> for f in fibs:    if f>1000:        print f        break    1597>>> it=iter([1,2,3])>>> it.next()1>>> it.next()2>>> class TestIterator:    value=0    def next(self):        self.value+=1        if self.value>10: raise StopIteration        return self.value    def __iter__(self):        return self    >>> ti=TestIterator()>>> list(ti)[1, 2, 3, 4, 5, 6, 7, 8, 9, 10]