title: How to find the location of missing values in a Data Frame in Python
body: <p>Hi I have a data frame test that has missing values in one column test1.  I need to find out where the missing values are located. I also need to know how many values are missing in the column test1. For example I ran the command pd.isnull(test.test1).  This returns the output below. </p>
  
  <pre><code>0  FALSE
  1  TRUE
  2  FALSE
  3  TRUE
  4  FALSE
  </code></pre>
  
  <p>From this I can see the locations of missing values are index 1 and 3 and the count of missing values is 2.</p>
  
  <p>What else do I need to add to my original statement to return this? i.e [1,3] and count of missing values 2.</p>
  
  <p>Thank you</p>