FileNotFoundError: [Errno 2] 文件 stock_dfs/BRK.B.csv 不存在：如果文件不存在如何调整代码：

Question

import bs4 as bs
import datetime as dt
import os
import pandas as pd
import pandas_datareader.data as web
import pickle
import requests


def save_sp500_tickers():
resp = 
requests.get('http://en.wikipedia.org/wiki/List_of_S%26P_500_companies')
soup = bs.BeautifulSoup(resp.text, 'lxml')
table = soup.find('table', {'class': 'wikitable sortable'})
tickers = []
for row in table.findAll('tr')[1:]:
    ticker = row.findAll('td')[0].text
    tickers.append(ticker)
with open("sp500tickers.pickle", "wb") as f:
    pickle.dump(tickers, f)
return tickers


 # save_sp500_tickers()
def get_data_from_yahoo(reload_sp500=False):
if reload_sp500:
    tickers = save_sp500_tickers()
else:
    with open("sp500tickers.pickle", "rb") as f:
        tickers = pickle.load(f)
if not os.path.exists('stock_dfs'):
    os.makedirs('stock_dfs')

start = dt.datetime(2010, 1, 1)
end = dt.datetime.now()
for ticker in tickers:
    # just in case your connection breaks, we'd like to save our progress!
    if not os.path.exists('stock_dfs/{}.csv'.format(ticker)):
        df = web.DataReader(ticker, 'yahoo', start, end)
        df.reset_index(inplace=True)
        df.set_index("Date", inplace=True)
        df = df.drop("Symbol", axis=1)
        df.to_csv('stock_dfs/{}.csv'.format(ticker))
    else:
        print('Already have {}'.format(ticker))


def compile_data():
with open("sp500tickers.pickle", "rb") as f:
    tickers = pickle.load(f)

main_df = pd.DataFrame()

for count, ticker in enumerate(tickers):
    df = pd.read_csv('stock_dfs/{}.csv'.format(ticker))

error occurs here it states "File stock_dfs/BRK.B.csv does not exist" but it wasnt imported / stored locally in the first place so why is this an issue? full error at the bottom

    df.set_index('Date', inplace=True)

    df.rename(columns={'Adj Close': ticker}, inplace=True)
    df.drop(['Open', 'High', 'Low', 'Close', 'Volume'], 1, inplace=True)

    if main_df.empty:
        main_df = df
    else:
        main_df = main_df.join(df, how='outer')

    if count % 10 == 0:
        print(count)
print(main_df.head())
main_df.to_csv('sp500_joined_closes.csv')


compile_data() 

pandas_datareader\compat__init__.py:7: FutureWarning: pandas.util.testing is deprecated. Use the functions in the public API at pandas.testing instead. from pandas.util.testing import assert_frame_equal 0 10 20 30 40 50 60 Traceback (most recent call last): File "C:\Users\Desktop\Python tutorials\Python finance Examples\py3tutorialSP500manip.py", line 75, in compile_data() File "C:\Users\Desktop\Python tutorials\Python finance Examples\py3tutorialSP500manip.py", line 57, in compile_data df = pd.read_csv('stock_dfs/{}.csv'.format(ticker)) File "C:\Users\AppData\Local\Programs\Python\Python38\lib\site-packages\pandas\io\parsers.py", line 676, in parser_f return _read(filepath_or_buffer, kwds) File "C:\Users\AppData\Local\Programs\Python\Python38\lib\site-packages\pandas\io\parsers.py", line 448, in _read parser = TextFileReader(fp_or_buf, **kwds) File "C:\Users\AppData\Local\Programs\Python\Python38\lib\site-packages\pandas\io\parsers.py", line 880, in init self._make_engine(self.engine) File "C:\Users\AppData\Local\Programs\Python\Python38\lib\site-packages\pandas\io\parsers.py", line 1114, in _make_engine s elf._engine = CParserWrapper(self.f, **self.options) File "C:\Users\AppData\Local\Programs\Python\Python38\lib\site-packages\pandas\io\parsers.py", line 1891, in init self._reader = parsers.TextReader(src, **kwds) File "pandas_libs\parsers.pyx", line 374, in pandas._libs.parsers.TextReader. cinit File "pandas_libs\parsers.pyx", line 674, in pandas._libs.parsers.TextReader._setup_parser_source FileNotFoundError: [Errno 2] File stock_dfs/BRK.B.csv does not exist: 'stock_dfs/BRK.B.csv'

following this tutorial:

https://pythonprogramming.net/combining-stock-prices-into-one-dataframe-python-programming-for-finance/

Answer 1

Right before the error occurs, a call is made to pd.read_csv() :

for count, ticker in enumerate(tickers):
    df = pd.read_csv('stock_dfs/{}.csv'.format(ticker))

The error occurs when ticker is 'BRK.B' and the program attempts to set read data from 'stocks_dfs/BRK.B.csv' .

The error message is saying that there is no stocks_dfs/BRK.B.csv file on your machine. This is puzzling since this bit of code should have downloaded all the necessary files:

for ticker in tickers:
    # just in case your connection breaks, we'd like to save our progress!
    if not os.path.exists('stock_dfs/{}.csv'.format(ticker)):
        df = web.DataReader(ticker, 'yahoo', start, end)
        df.reset_index(inplace=True)
        df.set_index("Date", inplace=True)
        df = df.drop("Symbol", axis=1)
        df.to_csv('stock_dfs/{}.csv'.format(ticker))
    else:
        print('Already have {}'.format(ticker))

Make sure you ran the download code (directly above) in the same directory you are running the read code (top). To run a quick check, see if there exists a folder called stock_dfs/ in you working directory. That folder should contain files like GOOGL.csv , FB.csv , and specifically BRK.B.csv .