title: How to create pandas dataframe with date as index
body: <p>This is my code,</p>
  
  <pre><code>import plotly.plotly as py
  import datetime
  import pandas
  import matplotlib.pyplot as plt
  import pandas.io.data as pd
  
  
  start = datetime.datetime(2016, 2, 1)
  end   = datetime.datetime(2016, 2, 11)
  #raw = pd.DataReader("tjx", "yahoo", start, end)
  rawy = pd.DataReader("tjx", "yahoo", start, end)['Low']
  
  print rawy
  print "========================"
  
  columns = ['Low']
  newDf = pd.DataFrame(columns=columns)
  newDf = newDf.fillna(0)
  
  #newDf[0] = rawy[0]
  #newDf[0:1] = rawy[0:1]
  #newDf.loc[0] = rawy.loc[0]
  newDf.loc[0] = rawy[0]
  print newDf
  </code></pre>
  
  <p>The result is like this,</p>
  
  <pre><code>Date
  2016-02-01    70.470001
  2016-02-02    72.309998
  2016-02-03    71.000000
  2016-02-04    69.720001
  2016-02-05    67.900002
  2016-02-08    66.820000
  2016-02-09    67.519997
  2016-02-10    69.279999
  2016-02-11    67.410004
  Name: Low, dtype: float64
  ========================
           Low
  0  70.470001
  </code></pre>
  
  <p>If you look at the last line of result, it's using 0 as index, not date from the original data frame. So how to correct this please ? </p>