title: Plot timeseries of histograms in Python
body: <p>I'm trying to plot a time-series of histograms in Python. <a href="https://stackoverflow.com/questions/11690194/time-series-histogram">There has been a similar question about this, but in R</a>. So, basically, I need the same thing, but I'm really bad in R. There are usually 48 values per day in my dataset. Where - 9999 represents missing data.  <a href="http://pastebin.com/vx9xLtdm" rel="nofollow noreferrer">Here's</a> the sample of the data.</p>
  
  <p>I started with reading in the data and constructing a <code>pandas</code> <code>DataFrame</code>. </p>
  
  <pre><code>import pandas as pd
  df = pd.read_csv('sample.csv', parse_dates=True, index_col=0, na_values='-9999') 
  print df
  
  &lt;class 'pandas.core.frame.DataFrame'&gt;
  DatetimeIndex: 336 entries, 2008-07-25 14:00:00 to 2008-08-01 13:30:00
  Data columns (total 1 columns):
  159.487691046    330  non-null values
  dtypes: float64(1)
  </code></pre>
  
  <p>Now I can group the data by day:</p>
  
  <pre><code>daily = df.groupby(lambda x: x.date())
  </code></pre>
  
  <p>But then I'm stuck. I don't know how to use this with <code>matplotlib</code> to get my timeseries of histograms. Any help appreciated, not necessarily using <code>pandas</code>.</p>