title: Python - Row calculation using Pandas
body: <p>I am working on large table using python (using pandas library).</p>
  
  <p>I would like to perform various kind of vector operations such as Correlation with each rows of the table.</p>
  
  <p>It might be a simple problem, but for me it is difficult to deal with the DataFrame structure. I do not have a good idea about how to convert each row (or column) into lists (or numpy arrays).</p>
  
  <p>Even counting the number of rows does not seem to be a simple problem, because function like <code>df.count()</code> seems to ignore null data.</p>
  
  <p>Simple data table and the expected result table are like below. In this case, I would like to calculate sum of each row pairs.</p>
  
  <p>The size of real table is much bigger (more than 1000 rows and columns) and contains some null values.</p>
  
  <hr>
  
  <p>Data.csv:</p>
  
  <pre><code>Label Col1 Col2
  Row1 1 2
  Row2 3 4
  Row3 5 6
  </code></pre>
  
  <hr>
  
  <p>Output.csv:</p>
  
  <pre><code>Label Col3
  Row1,Row2 4,6
  Row1,Row3 6,8
  Row2,Row3 8,10
  </code></pre>