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首页 > 解决方案 > 在 GOOGLE COLAB 中运行此 python 代码时，它显示错误。谁能告诉我我做错了什么并分享更正的代码？

python - 在 GOOGLE COLAB 中运行此 python 代码时，它显示错误。谁能告诉我我做错了什么并分享更正的代码？

问题描述

import pandas_datareader.data as web
import numpy as np
import pandas as pd

stock = ['AAPL']

data = web.DataReader(stock,data_source="yahoo",start='01/01/2010')['Adj Close']
data.sort_index(inplace=True)

returns = data.pct_change()
mean_return = returns.mean()

return_stdev = returns.std()
annualised_return = round(mean_return * 252,2)

annualised_stdev = round(return_stdev * np.sqrt(252),2)

print ('The annualised mean return of stock {} is {}, ' 
        'and the annualised volatility is {}').format(stock[0],annualised_return,annualised_stdev)

标签： pythongoogle-colaboratoryfinance

解决方案

您通过将其放在右括号之后来调用函数format的输出。不返回任何内容，因此您实际上是在调用（不存在）。您应该直接在字符串上调用格式，如下所示：printprintNone.format(...)

print('The annualised mean return of stock {} is {}, and the annualised volatility is {}'.format(stock[0],annualised_return,annualised_stdev))

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