Pandas .join Not Working To Combine S&p500 Stock Data

I'm following the finance tutorials on PythonProgramming.net and have run into an issue when I try to combine several dataframes into one large dataframe. I created a function to d

Solution 1:

IIUC:

You don't want to use join and you couldn't anyway if you start with an empty dataframe. Use pd.concat instead:

main_df = pd.concat([main_df, df], axis=1)

However, I would recommend this to replace your whole process:

def read_file(ticker):
    df = pd.read_csv('stock_dfs/{}.csv'.format(ticker)).set_index('Date')
    return df.Close.rename(ticker)

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

main_df = pd.concat([read_file(t) for t in tickers], axis=1)