How I can calculate standard deviation for rows of a dataframe?
<pre><code>df:  

name   group   S1   S2  S3        
A      mn      1    2   8         
B      mn      4    3   5        
C      kl      5    8   2        
D      kl      6    5   5         
E      fh      7    1   3         

output: 

std (S1,S2,S3)
3.78
1
3
0.57
3.05
</code></pre>

<p>This is working for getting std for a column:</p>

<pre><code>numpy.std(df['A'])
</code></pre>

<p>I want to do the same for rows</p>