尝试创建看涨期权收益配置文件，但不断收到此错误

问题描述

我正在尝试在 Python 中创建一个收益配置文件，但不断得到：

"ufunc 'subtract' did not contain a loop with signature matching types (dtype('<U32'),dtype('<U32')) -> dtype('<U32')" 

当我声明变量 callPayoff 时。这是我的代码如下：

import pandas as pd
import numpy as np
import yfinance as yf
import matplotlib.pyplot as plt

pd.options.mode.chained_assignment = None
tickers = input("Enter Ticker in CAPS: ")
print (tickers)

inTradata = yf.download(tickers = tickers,period = '7d',interval = '1m')

curPrice = inTradata.iloc[-1,inTradata.columns.get_loc("Close")]
strikePrice = input("What is your Strike Price?: ")

lowerbound = curPrice * 0.8
upperbound = curPrice * 1.2

curPrice_PP = np.arange(lowerbound,upperbound,0.01)

#use a lambda for a call payoff function:
callPayoff = lambda curPrice,strikePrice: np.maximum(curPrice_PP - strikePrice,0)

#use a lambda for a put payoff function
putPayoff = lambda curPrice,strikePrice: np.maximum(strikePrice - curPrice_PP,0)

#plot the call payoff
plt.figure(1)
plt.title('Call Option Payoff at Expiration')
plt.xlabel("Underlying stock price")
plt.ylabel("Price of Option at Expiration")
plt.plot(curPrice_PP,callPayoff(curPrice_PP,strikePrice))

解决方法

这个更简单的示例是否让您了解错误发生的位置和原因？

In [261]: np.arange(10)-'astromg'
Traceback (most recent call last):
  File "<ipython-input-261-b7b809d0f016>",line 1,in <module>
    np.arange(10)-'astromg'
UFuncTypeError: ufunc 'subtract' did not contain a loop with signature matching types (dtype('<U21'),dtype('<U21')) -> dtype('<U21')

,

正如@hpaulj 所说，你不能减去字符串！当我提示用户输入执行价格时，它会将输入保存为字符串，我只是将其更改为：

strikePrice = int(input("What is your Strike Price?: "))