在Python中将函数的结果存储到可检索的数据帧中[重复]

Question

from googlefinance import getQuotes
import json
import pandas as pd
import datetime
import requests

def get_intraday_data(symbol, interval_seconds=301, num_days=10):
    # Specify URL string based on function inputs.
    url_string = 'http://www.google.com/finance/getprices?q=   {0}'.format(symbol.upper())
    url_string += "&i={0}&p={1}d&f=d,o,h,l,c,v".format(interval_seconds,num_days)

    # Request the text, and split by each line
    r = requests.get(url_string).text.split()

    # Split each line by a comma, starting at the 8th line
    r = [line.split(',') for line in r[7:]]

    # Save data in Pandas DataFrame
    df = pd.DataFrame(r, columns=    ['Datetime','Close','High','Low','Open','Volume'])

    # Convert UNIX to Datetime format
    df['Datetime'] = df['Datetime'].apply(lambda x: datetime.datetime.fromtimestamp(int(x[1:])))

    return df

---------------------------------------------------------------------------
    NameError                                 Traceback (most recent call last)
<ipython-input-40-db884686c2f6> in <module>()
     18     return df
     19 
---> 20 symbol = pd.DataFrame(df)

NameError: name 'df' is not defined

Answer 1

我对计算机科学术语不够熟悉，无法向您彻底解释这一点，但基本上，当您调用具有返回值的函数时，该值必须保存为变量。

df只存在于您的函数中。（我认为这叫做范围）。当您离开函数时，df将消失

你在做什么

get_intraday_data(symbol, 301,10)

df = get_intraday_data(symbol, 301,10)

然后你就可以用它做事情了

或者，不是返回df，而是将其泡菜化。在您的“get_intraday_symbol”中

fname = 'file1.P'
df.to_pickle(fname)
return fname

然后，后续代码必须读取picked数据帧

fname = get_intraday_data(symbol, 301,10)
df = pd.read_pickle(fname)