Python 减去浮点数

发布于 2024-10-31 11:57:10 字数 375 浏览 6 评论 0原文

我将以下代码嵌入到类中。每当我运行 distToPoint 时，它都会给出错误“不支持的操作数类型 -: 'NoneType' 和 'float'” 我不知道为什么它会以 NoneType 返回，我该怎么办让减法起作用？

self 和 p 都应该是成对的。

def __init__(self, x, y):
    self.x = float(x)
    self.y = float(y)
def distToPoint(self,p):
    self.ax = self.x - p.x
    self.ay = self.y - p.y
    self.ac = math.sqrt(pow(self.ax,2)+pow(self.ay,2))

原文

I have the following code embeded in a class.Whenever I run distToPoint it gives the error 'unsupported operand type(s) for -: 'NoneType' and 'float'' I don't know why it's returning with NoneType and how do I get the subtraction to work?

Both self and p are supposed to be pairs.

def __init__(self, x, y):
    self.x = float(x)
    self.y = float(y)
def distToPoint(self,p):
    self.ax = self.x - p.x
    self.ay = self.y - p.y
    self.ac = math.sqrt(pow(self.ax,2)+pow(self.ay,2))

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戏剧牡丹亭 2024-11-07 11:57:10

为了比较，

import math

class Point(object):
    def __init__(self, x, y):
        self.x = x + 0.
        self.y = y + 0.

    def distToPoint(self, p):
        dx = self.x - p.x
        dy = self.y - p.y
        return math.sqrt(dx*dx + dy*dy)

a = Point(0, 0)
b = Point(3, 4)

print a.distToPoint(b)

5.0

For sake of comparison,

import math

class Point(object):
    def __init__(self, x, y):
        self.x = x + 0.
        self.y = y + 0.

    def distToPoint(self, p):
        dx = self.x - p.x
        dy = self.y - p.y
        return math.sqrt(dx*dx + dy*dy)

a = Point(0, 0)
b = Point(3, 4)

print a.distToPoint(b)

returns