title: Standard deviation for DF, pandas
body: <p>for example I have a pandas DataFrame, which looks as:</p>
  
  <pre><code>a b c
  1 2 3
  4 5 6
  7 8 9
  </code></pre>
  
  <p>I want to calculate the standard deviation for all values in this DF. The function <code>df.std()</code> get me back the values pro column.</p>
  
  <p>Of course I can create the next code:</p>
  
  <pre><code>sd = []
  sd.append(list(df['a']))
  sd.append(list(df['b']))
  sd.append(list(df['c']))
  numpy.std(sd)
  </code></pre>
  
  <p>Is it possible to do this code simpler and use some pandas function for this DF?</p>