Question

这是我写的。关于几何对象的程序，我试图在Circle的str函数中使用GeometricObject。 str （self），但它不起作用。我尝试了很多方法，但仍然有一些错误。

import math

class GeometricObject(object):
     def __init__(self, color = "white", filled = True):
        self.color = color
        self.filled = filled

     def getColor(self):
        return self.color

     def setColor(self, color):
        self.color = color

     def isFilled(self):
        return self.filled

     def setFilled(self, filled):
        self.filled = filled

     def __str__(self):
       return "color: " + self.color + \
             " and filled: " + str(self.filled)

class Circle(object):
     def __init__(self, radius = 1, color = "white", filled = True):
         self.radius = radius
         self.color = color
         self.filled = filled

     def __str__(self):
         return "Circle: radius = " + str(self.radius) + \
               GeometricObject.__str__(self)

     def getArea(self):
         return (math.pi * self.radius**2)

     def getPerimeter(self):
         return (math.pi * 2 * self.radius)

class Triangle(object):

   def __init__(self, side1 = 1, side2 = 1, side3 = 1, color = "white", filled = True):
    self.side1 = side1
    self.side2 = side2
    self.side3 = side3
    self.color = color
    self,filled = filled

   def __str__(self):
    return "Triangle: side1 = " + str(self.side1) + \
           " side2 = " + str(self.side2) + \
           " side3 = " + str(self.side3) + \
           " color: " + str(self.color) +\
           " filled: " + str(self.filled)

   def getArea(self):
    s = (side1 + side2 + side3) / 2
    area = sqrt(s(s - side1)(s - side2)(s - side3))
    return area

def getPerimter(self):
    return (side1 + side2 + side3)

def main():
#Testing Circle class
print "Entering input values for a circle"
r = input('Enter value for radius: ')

c1 = Circle(r)

print c1
print "%.2f" % c1.getArea()
print "%.2f" % c1.getPerimeter()
print c1.getColor()
print c1.isFilled()

#Testing Triangle class
print "\nEntering input values for a traingle"
s1 = input('Enter value for side1: ')
s2 = input('Enter value for side2: ')
s3 = input('Enter value for side3: ')
color = raw_input('Enter color of the triangle: ')
filled = input('Is the triangle filled (1/0)? ')
filled = (filled == 1)

t1 = Triangle(s1, s2, s3, color, filled)

print t1
print "%.2f" % t1.getArea()
print "%.2f" % t1.getPerimeter()
print t1.getColor()
print t1.isFilled()

main()

但它一直告诉我，

Entering input values for a circle
Enter value for radius: 1
Traceback (most recent call last):
  File "C:\Users\wxwdd_000\Desktop\CSC131\Lab_5.py", line 94, in <module>
    main()
  File "C:\Users\wxwdd_000\Desktop\CSC131\Lab_5.py", line 71, in main
    print c1
  File "C:\Users\wxwdd_000\Desktop\CSC131\Lab_5.py", line 32, in __str__
    GeometricObject.__str__(self)
TypeError: unbound method __str__() must be called with GeometricObject instance as first argument (got Circle instance instead)
>>>

如何修复 str 功能？

Answer 1

您忘记了子类继承自GeometricObject。

更改这些：

class Circle(object):
class Triangle(object):

到这些：

class Circle(GeometricObject):
class Triangle(GeometricObject):

附加说明：您应该致电GeometricObject.__init__来设置属性Triangle和Circle继承自GeometricObject，而不是直接分配它们。如果GeometricObject.__init__使用其参数做了更复杂的事情，子类构造函数将无法正确处理它或者与超类的实现细节过于依赖。

Answer 2

我想继承它应该是这样的 class circle(GeometricObject):也可以使用super()内置函数调用调用GeometricObjects str方法，如super(circle,self).str(arg)

希望这有帮助

如何在其他类中使用类的返回？

2 个答案: