＃錯誤：類型錯誤：不受約束的方法__init __（）必須與形狀例如被稱爲第一個參數（有代替STR實例）＃

Question

這是我的腳本：

class shape: 
    def __init__(self, name): 
     self.name = name 

    def printMyself(self): 
     print 'I am a shape named %s.' % self.name 

shape1 = shape(name = 'myFirstShape.') 
shape2 = shape(name = 'mySecondShape.') 
shape1.printMyself() 
shape2.printMyself() 


class polyCube(shape): 
    def __init__(self, name, length, width, height): 
     shape.__init__(name) 
     self.length = length 
     self.width = width 
     self.height = height 

    def printMyself(self): 
     shape.printMyself(self) 
     print 'I am also a cube with dimensions %.2f, %.2f, %.2f.' % (length, width, height) 


class polySphere(shape): 
    def __init__(self, name, radius): 
     shape.__init__(name) 
     self.radius = radius 

    def printMyself(self): 
     shape.printMyself(self) 
     print 'I am also a sphere with dimensions of %.2f.' % (radius) 

cube1 = polyCube('firstCube', 2.0, 1.0, 3.0) 
cube2 = polyCube('secondCube', 3.0, 3.0, 3.0) 
sphere1 = polySphere('firstSphere', 2.2) 
sphere2 = polySphere('secondSphere', 3.5) 
shape1 = shape('myShape') 
cube1.printMyself() 
cube2.printMyself() 
sphere1.printMyself() 
sphere2.printMyself() 

我的錯誤：

# Error: TypeError: unbound method __init__() must be called with shape instance as first argument (got str instance instead) # 

我不明白。 爲什麼我得到這個錯誤信息？ 解決方案是什麼？ 爲什麼？

謝謝！

Answer 1

你的代碼的工作版本，我在評論

class shape: 
    def __init__(self, name): 
    self.name = name 

    def printMyself(self): 
    print ('I am a shape named %s.' % self.name) 

shape1 = shape(name = 'myFirstShape.') 
shape2 = shape(name = 'mySecondShape.') 
shape1.printMyself() 
shape2.printMyself() 


class polyCube(shape): 
    def __init__(self, name, length, width, height): 
     shape.__init__(self,name) #pass self here, you're calling parent's __init__() explicitly so you should pass self. 

     self.length = length 
     self.width = width 
     self.height = height 

    def printMyself(self): 
    shape.printMyself(self) 
    #use self.length ,self.width instead of just length,width etc 
    print ('I am also a cube with dimensions %.2f, %.2f, %.2f.' % (self.length, self.width, self.height)) 


class polySphere(shape): 
    def __init__(self, name, radius): 
     shape.__init__(self,name) #pass self here 

     self.radius = radius 

    def printMyself(self): 
    shape.printMyself(self) 
    print ('I am also a sphere with dimensions of %.2f.' % (self.radius)) #use self.radius here 

cube1 = polyCube('firstCube', 2.0, 1.0, 3.0) 
cube2 = polyCube('secondCube', 3.0, 3.0, 3.0) 
sphere1 = polySphere('firstSphere', 2.2) 
sphere2 = polySphere('secondSphere', 3.5) 
shape1 = shape('myShape') 
cube1.printMyself() 
cube2.printMyself() 
sphere1.printMyself() 
sphere2.printMyself() 

Answer 2

一般解釋了錯誤，你應該張貼的全回溯。它使事情更容易調試。問題（比我假設從複製/粘貼錯誤附帶的壓痕等）是當你撥打：

shape.__init__(name) 

當你從形狀繼承。

如果你看shape.__init__的「原型」，它看起來像shape.__init__(self,name) - 所以這就是你應該使用的。錯誤來了，因爲你傳遞name（字符串），你應該通過self（一PolyCube，因此也shape由於繼承）

ASIDE

此外，在python 2.X ，總是從object繼承是一個好習慣。例如：

class shape(object): 
    ... 

這允許你使用與新風格類相關的所有優點。 （在Python 3中，所有類都是新類）