title: Keep getting the ValueError 'Index contains duplicate entries, cannot reshape'
body: <p>I want to pull ticker data from the all the sp500 stocks from yahoo.</p>
  
  <p>I saved the sp500 ticker symbols into a list from a local csv file that I made.</p>
  
  <p>When when I run the following code, I get the: </p>
  
  <blockquote>
    <p>ValueError 'Index contains duplicate entries, cannot reshape'</p>
  </blockquote>
  
  <p>However, I noticed that this problem doesn't seem to occur with shorter stock lists but can't figure why; some help would be fully appreciated.</p>
  
  <pre><code>import pandas as pd
  import numpy as np
  from pandas_datareader import data
  from statsmodels.tsa.stattools import coint
  import matplotlib.pyplot as plt
  from pyfinance.ols import PandasRollingOLS
  
  sp500=pd.read_csv('sp500 stocks list.csv')
  sp500_list=[]
  for i in sp500:
      sp500_list.append(i)
  
  dataframe=data.DataReader(sp500_list, 'yahoo',start='2020/01/01')
  print(dataframe)
  </code></pre>
  
  <p>I have tried <code>dataframe = dataframe.drop_duplicates(sp500_list)</code> however i still gives me the same <code>ValueError</code></p>