需要為 Panda 數據框打印一個新列

Question

我通過應用 function 使用以下代碼打印比率，但出現以下錯誤。

代碼

import investpy
import pandas as pd
import numpy as np
import sys

def main(stock1_name, stock2_name):
    stock1 = investpy.get_stock_historical_data(stock=stock1_name,country='india', from_date='01/01/2020',to_date='08/03/2021')
    stock2 = investpy.get_stock_historical_data(stock=stock2_name,country='india', from_date='01/01/2020',to_date='08/03/2021')
    new_df = pd.merge(stock1, stock2, on='Date')
    new_df = new_df.drop(['Open_x', 'High_x', 'Low_x', 'Volume_x', 'Currency_x', 'Low_y','Volume_y', 'Currency_y', 'Open_y', 'High_y'], axis = 1)
    new_df['ratio'] = np.log10(new_df['Close_x']/new_df['Close_y'])
    return new_df
    x = main("IOC","HPCL")
print(x)

錯誤

NameError                                 Traceback (most recent call last)
<ipython-input-2-c17535375449> in <module>
     12     return new_df
     13     x = main("IOC","HPCL")
---> 14 print(x)

NameError: name 'x' is not defined

Answer 1

1. 您在 function main內部調用x = main("IOC","HPCL")
2. 這使得x僅在 function main的 scope 內部定義
3. 當您在 function main之外調用 print(x) 時，解釋器會拋出錯誤，即x未定義

此更正是否解決了問題：

import investpy
import pandas as pd
import numpy as np
import sys

def main(stock1_name, stock2_name):
    stock1 = investpy.get_stock_historical_data(stock=stock1_name,country='india', from_date='01/01/2020',to_date='08/03/2021')
    stock2 = investpy.get_stock_historical_data(stock=stock2_name,country='india', from_date='01/01/2020',to_date='08/03/2021')
    new_df = pd.merge(stock1, stock2, on='Date')
    new_df = new_df.drop(['Open_x', 'High_x', 'Low_x', 'Volume_x', 'Currency_x', 'Low_y','Volume_y', 'Currency_y', 'Open_y', 'High_y'], axis = 1)
    new_df['ratio'] = np.log10(new_df['Close_x']/new_df['Close_y'])
    return new_df

x = main("IOC","HPCL") # Edit moving this line outside the function main()
print(x)