Question

我需要添加一个 eq 方法，如果坐标引用平面中的同一点（即，具有相同的x和y坐标），并且返回结果感到困惑，则该方法返回True。

我使用 eq 尝试了一些代码，但仍然出现错误，我不确定为什么。

class Coordinate(object):
        def __init__(self, x, y):
            self.x = x
            self.y = y
    def getX(self):
        # Getter method for a Coordinate object's x coordinate.
        # Getter methods are better practice than just
        # accessing an attribute directly
        return self.x
    def getY(self):
        # Getter method for a Coordinate object's y coordinate
        return self.y
    def __str__(self):
        return '<' + str(self.getX()) + ',' + str(self.getY()) + '>'
    def __eq__(Coordinate, otherPoint):
        if self.GetX() == otherPoint.getX()&& self.GetY() == otherPoint.getY()
            return True

x=5
y=5

如果两个坐标都是相同的数字，则预期输出将返回true；如果x和y不是相同的数字，则预期输出将返回false。

Answer 1

您的代码中的某些问题/解决方法

您实际上不需要GetX和GetY，可以直接引用属性x和y。
&&在Python中不是有效的语法，而是使用and
__eq__的第一个参数为self
如果您使用的是python3.6 +，则可以使用f-strings格式化字符串，否则可以使用格式化字符串
您可以选择引发TypeError以确保other的类型为Coordinate

因此更新后的代码如下

class Coordinate(object):
    def __init__(self, x, y):
        self.x = x
        self.y = y

    def __str__(self):
        #Use a f-string to format your string representation
        return f'<{self.x},{self.x}>'

        #If python3.5 and below, you can use format string as below
        #return '<{},{}>'.format(self.x, self.y)

    def __eq__(self, other):
        #If other is not an instance of Coordinate, raise TypeError
        if not isinstance(other, Coordinate):
            raise TypeError('An instance of class Coordinate is expected')
        #Compare both coordinates and return True or False
        return self.x == other.x and self.y == other.y

然后您可以使用如下所示的类

c1 = Coordinate(5,5)
c2 = Coordinate(6,6)

print(c1)
#<5,5>
print(c2)
#<6,6>
print(c1 == c1)
#True
print(c1 == c2)
#False
print(c1 == 1)
#TypeError: An instance of class Coordinate is expected

Answer 2

>>> class Coordinate:
...     def __init__(self, x, y):
...         self.x = x
...         self.y = y
...     def __eq__(self, other):
...         if not isinstance(other, Coordinate):
...             raise TypeError('You can compare a Coordinate with only another Coordinate')
...         return self.x == other.x and self.y == other.y
...
>>> Coordinate(1,2) == Coordinate(1,2)
True
>>> Coordinate(1,2) == Coordinate(1,3)
False
>>> Coordinate(1,2) == 'Hello'
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "<stdin>", line 7, in __eq__
TypeError: You can compare a Coordinate with only another Coordinate
>>>

Answer 3

这么多小错误...

GetX与getX
if语句的末尾需要:
__init__子句的缩进是错误的
&&在python中不存在，称为and
__eq__函数并不总是返回，它需要一个else子句，或者只是直接返回布尔表达式
__eq__的第一个参数必须为self

class Coordinate(object):
    def __init__(self, x, y):
        self.x = x
        self.y = y
    def getX(self):
        # Getter method for a Coordinate object's x coordinate.
        # Getter methods are better practice than just
        # accessing an attribute directly
        return self.x
    def getY(self):
        # Getter method for a Coordinate object's y coordinate
        return self.y
    def __str__(self):
        return '<' + str(self.getX()) + ',' + str(self.getY()) + '>'
    def __eq__(self, otherPoint):
        return self.getX() == otherPoint.getX() and self.getY() == otherPoint.getY()

使用eq在Python中修改类

3 个答案:

使用__eq__在Python中修改类

3 个答案:

使用eq在Python中修改类