"只能将size-1数组转换为Python标量& quot; [英] "Only size-1 arrays can be converted to Python scalars"

问题描述

我有此代码:

R = float(input("Enter the arc's radius of curvature: "))

H = float(input("Enter the arc's height: "))

import matplotlib.pyplot as plt

import numpy as np

import math

#cc = center of curvature

cc = math.sqrt(R**2 - (H / 2)**2)

x = np.linspace(-5,5,100)

y = math.sqrt(R**2 - (x - cc)**2)

plt.plot(x, y, 'c')

plt.show()

并收到此错误:

TypeError:只有大小为1的数组可以转换为Python标量

TypeError: only size-1 arrays can be converted to Python scalars

我该如何解决?

推荐答案

您可以计算 y = math.sqrt(R ** 2-(x-cc)** 2) x 在单个变量中，但是在您的代码中，您尝试计算表示 x array 的每个元素的表达式(并获得一个数组结果).

You can compute y = math.sqrt(R**2 - (x - cc)**2) as long as x in a single variable, but in your code you attempt to compute this expression for each element of x array (and get an array of results).

为此，请按照下列步骤操作:

To to this, proceed as follows:

1. 将表达式定义为函数:

1. Define your expression as a function:

 def myFun(R, x, cc):
     return math.sqrt(R**2 - (x - cc)**2)

定义此功能的矢量化版本:

 myFn = np.vectorize(myFun, excluded=['R', 'cc'])

将 y 计算为:

 y = myFn(R, x, cc)

对于 R = 20.0 ， H = 30.0 和 x = np.linspace(-5,5,10)(较短的数组))我知道了:

For R = 20.0, H = 30.0 and x = np.linspace(-5,5,10) (a shorter array) I got:

array([ 8.22875656, 10.34341406, 11.99128261, 13.34639903, 14.49112624,
       15.47223243, 16.31925481, 17.05218586, 17.6852162 , 18.22875656])

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