title: How to calculate standard deviation with pandas for each row?
body: <p>I have my dataframe:</p>
  
  <pre><code>d = {'y1': [0,4.2, 6.7, 5.27, 3.45,3.45, 1.22], 'y2': [2, 8, 9, 7, 2, 1, 4]}
  df = pd.DataFrame(data=d)
  print(df)
  </code></pre>
  
  <p>I want to calculate the standard deviation for each row (as in between 2 data points). I have used this :</p>
  
  <pre><code>df.stack().std()  
  </code></pre>
  
  <p>But this gives me the standard deviation for the whole dataframe i am afraid. I just want to get the error for each data point and plot the error bars, so i am looking to calculate the standard deviation for each row. How to do this?</p>