【问题标题】：python bound method Errorpython绑定方法错误
【发布时间】：2017-07-19 21:46:42
【问题描述】：

我对 python 2.7 和类中的 def 函数有疑问，因为绑定方法存在问题。这是学校的作业：D

代码如下：

从 abc 导入 ABCMeta，抽象方法导入数学

class Shapes(object):
    __metaclass__= ABCMeta
    @abstractmethod

    def __init__(self):
        pass

class TwoDShapes(Shapes):
    def __init__(self):
        pass

class ThreeDShapes(Shapes):
def __init__(self):
        pass
================= Main.py =====================
from BasicClassShapes import*

class Rectangle(TwoDShapes):
    def __init__(self, nameOfShape, length, width, numberofSides, numberOfVertices):
        self.nameOfShape = "Rectangle"
        self.length = length
        self.width = width
        self.numberofSides = 4
        self.numberOfVertices = 4
        super(Rectangle,self).__init__()

    def perimeter(self):
        self.perimeter = length*2 + width*2
    def Area(self):
        self.Area = length*width

====================================

def PrintALL():

    A = Rectangle("Rectangle", "10", "20", "4",  "4")

    print "This is the name of the shape: ", A.nameOfShape
    print "This is the length: ", A.length
    print "This is the width: ", A.width
    print "This is the number of side: ", A.numberofSides
    print "This is the number of vertice: ", A.numberOfVertices
    print "This is the perimeter: ", A.perimeter
    print "This is the area: ", A.Area
    print "\n"
PrintALL()


=============== Result =======================
This is the name of the shape:  Rectangle
This is the length:  10
This is the width:  20
This is the number of side:  4
This is the number of vertice:  4
This is the perimeter:  <bound method Rectangle.perimeter of <__main__.Rectangle object at 0x03BEFC90>>

This is the area:  `<bound method Rectangle.Area of <__main__.Rectangle object at 0x03BEFC90>>`

【问题讨论】：

对不起这是我第一次使用这个网站= =
间距太小，因为我不知道如何处理选项卡
不用担心，点击帖子下方的“编辑”并使用{} 按钮正确格式化代码。有一个预览会告诉你它是否有效
Bound method error的可能重复
只是缺少一些括号。 perimeter 和 Area 是函数，你要调用它们

标签： python

【解决方案1】：

您可以在外围函数中使用返回值：

def perimeter(self):
    return self.length*2 + self.width*2

然后调用A.perimeter() 而不是A.perimeter。

print "This is the perimeter: ", A.perimeter()

对于区域也是如此。

def Area(self):
    return self.length*self.width


print "This is the area: ", A.Area()

编辑：对不起，我匆忙回答，没有费心检查它。这是Rectangle 类和PrintALL() 函数的有效替代品。我也在上面编辑过。

最好将数字类型（而不是字符串）传递给函数，并且可以通过使用浮点数而不是整数来避免舍入错误。

class Rectangle(TwoDShapes):
    def __init__(self, nameOfShape, length, width, numberofSides, numberOfVertices):
        self.nameOfShape = "Rectangle"
        self.length = length
        self.width = width
        self.numberofSides = 4
        self.numberOfVertices = 4
        super(Rectangle,self).__init__()

    def perimeter(self):
        return self.length*2.0 + self.width*2.0
    def Area(self):
        return self.length*self.width

def PrintALL():

    A = Rectangle("Rectangle", 10.0, 20.0, 4.0, 4.0)

    print "This is the name of the shape: ", A.nameOfShape
    print "This is the length: ", A.length
    print "This is the width: ", A.width
    print "This is the number of side: ", A.numberofSides
    print "This is the number of vertice: ", A.numberOfVertices
    print "This is the perimeter: ", A.perimeter()
    print "This is the area: ", A.Area()
    print "\n"
PrintALL()

输出：

This is the name of the shape:  Rectangle
This is the length:  10.0
This is the width:  20.0
This is the number of side:  4
This is the number of vertice:  4
This is the perimeter:  60.0
This is the area:  200.0

【讨论】：

NameError: 未定义全局名称“长度”
@LDs self.length等
def perimeter(self): return self.length*2 + self.width*2 def Area(self): return self.length*self.width print "这是周长：", A .perimeter() print "这是区域：", A.Area() TypeError: can't multiply sequence by non-int of type 'str'
好的，我用 int() 修复了它。 self.length = int(length) self.width = int(width)
你能帮我解决这个问题吗？ stackoverflow.com/questions/42519118/…

【解决方案2】：

如果形状不会改变，它们就不需要是函数：

class Rectangle(TwoDShapes):
    def __init__(self, nameOfShape, length, width, numberofSides, numberOfVertices):
        super(Rectangle,self).__init__()
        self.nameOfShape = "Rectangle"
        self.length = length
        self.width = width
        self.numberofSides = 4
        self.numberOfVertices = 4
        self.perimeter = length*2 + width*2
        self.Area = length*width

将使用您编写的代码。您不需要函数，因为您可以在 perimeter 和 Area 初始化时对其进行数学运算。

【讨论】：

感谢您的帮助，但是我们老师说我们必须包括功能（体积，面积，表面积，周长，打印全部），这是在纸上打出的要求。
我猜他们想要函数，因为如果修改了长度或宽度，则可以通过再次调用它们的函数来重新计算周长和面积值。
@feedMe 是的。如果您希望能够修改形状，它们应该是函数。

【解决方案3】：

from BasicClassShapes import*

###############################################

class Rectangle(TwoDShapes):
    def __init__(self, nameOfShape, length, width, numberofSides, numberOfVertices):
        self.nameOfShape = "Rectangle"
        self.length = int(length)
        self.width = int(width)
        self.numberofSides = 4
        self.numberOfVertices = 4
        super(Rectangle,self).__init__()

    def perimeter(self):
        return self.length*2 + self.width*2
    def Area(self):
        return  self.length*self.width

###########################################

def PrintALL():

    A = Rectangle("Rectangle", "10", "20", "4",  "4")

### Specs of Rectangle ###
    print "This is the name of the shape: ", A.nameOfShape
    print "This is the length: ", A.length
    print "This is the width: ", A.width
    print "This is the number of side: ", A.numberofSides
    print "This is the number of vertice: ", A.numberOfVertices
    print "This is the perimeter: ", A.perimeter()
    print "This is the area: ", A.Area()
    print "\n"
PrintALL()

【讨论】：

【解决方案4】：

class New:
    def __init__(self,a,b):
        self.a = a
        self.b = b


    def addition(self):
        return (self.a + self.b)

p = New(3,4)

print(p.a)
print(p.b)

print(p.addition())

看这段代码sn-p，需要用()调用函数，函数为p.addition()，变量为p.a

【讨论】：