python如何在两个类之间相互调用？

Question

有 2 个类：class A和class B. 在class A，我想调用一个方法class B。同时，在class B，我想调用一个方法class A。喜欢：

class A(object):
    """docstring for A"""
    def __init__(self):
        self.str_A = 'this is class A'
    def printA(self):
        print self.str_A
    def callB(self):
        B.printB()

class B(object):
    """docstring for B"""
    def __init__(self):
        self.str_B = 'This is class B'
    def printB(self):
        print self.str_B
    def callA(self):
        A.printA()

我怎样才能做到这一点？

嗯，我修改一下我的表达方式。

class A(object):
    """docstring for A"""
    def __init__(self):
        self.str_A = 'this is class A'
    def printA(self):
        print self.str_A
    There is a function to call printB in class B names CB.
class B(object):
    """docstring for B"""
    def __init__(self):
        self.str_B = 'This is class B'
    def printB(self):
        print self.str_B
    There is a function to call printA in class A names CA.

aaa = A()
bbb = B()
aaa.CB() or bbb.CA()

上面的语句当然是错误的，请问如何实现？python如何在两个类之间相互调用？

这是我的两节课？ class Stock是一类以接收股票数据？并且RtnTick在class Stock可以自动更新。class TradeSystem是一类做一个GUI，然后点击按钮时，该程序可以使股票exchange.GUI必须实时显示数据，所以当RtnTick更新的数据，我想打电话给self.e1_str.set()在class TradeSystem显示。当我按一下按钮，我会打电话给TradeCommit在class Stock做出deal.And我省略了很多其他codes.These两个类是large.And的...你有一个想法来解决这个问题？我是新在python中。谢谢。

class Stock(LtsAPI):   
    def RtnTick(self,t):
        global Sto,Configs_Path,Sto,AskPri,BidPri,AskVol,BidVol
        contract = t.InstrumentID
        if(contract in Sto):
        #Here I want to call **self.e1_str.set()** in class TradeSystem.
    def TradeCommit(self):
        #This is a function to trading.      


class TradeSystem(object):
    def __init__(self):

        self.root = Tk()

        self.e1_str = StringVar()
        self.e1 = Entry(self.root,textvariable = self.e1_str)
        self.e1.bind('<KeyPress>')  
        self.e1.grid(row = 1, column = 0)

        #**self.e1_str.set()** can set the content to display.

    def Trade(self):
        self.button = Button(self.root,command = *call **TradeCommit** in class Stock*)
        #command is the function to run when triggered.

Answer 1

您正在寻找类方法（另一种语言中的静态方法）

class A(object):
    """docstring for A"""
    def __init__(self):
        self.str_A = 'this is class A'
    def printA(self):
        print self.str_A
    @classmethod
    def CB(cls):
        B().printB()

class B(object):
    """docstring for B"""
    def __init__(self):
        self.str_B = 'This is class B'
    def printB(self):
        print self.str_B
    @classmethod
    def CA(cls):
        A().printA()

aaa = A()
bbb = B()
aaa.CB() or bbb.CA()
>>> This is class B
>>> this is class A

但是由于 printA() 和 printB() 需要一个实例，因此您需要实例化一个对象来调用它们