title: fill missing indices in pandas
body: <p>I have data like follows:</p>
  
  <pre><code>import pandas as pd
  from datetime import datetime
  
  x = pd.Series([1, 2, 4], [datetime(2013,11,1), datetime(2013,11, 2), datetime(2013, 11, 4)])
  </code></pre>
  
  <p>The missing index at November 3rd corresponds to a zero value, and I want it to look like this:</p>
  
  <pre><code>y = pd.Series([1,2,0,4], pd.date_range('2013-11-01', periods = 4))
  </code></pre>
  
  <p>What's the best way to convert x to y?  I've tried</p>
  
  <pre><code>y = pd.Series(x, pd.date_range('2013-11-1', periods = 4)).fillna(0)
  </code></pre>
  
  <p>This throws an index error sometimes which I can't interpret (Index length did not match values, even though index and data have the same length.  Is there a better way to do this?</p>