title: Julia iterate over rows of dataframe
body: <p>I am trying to iterate over the rows of a DataFrame in Julia to generate a new column for the data frame. I haven't come across a clear example of how to do this. In R this type of thing is vectorized but from my understanding not all of Julia's operations are vectorized so I need to loop over the rows. I know I can do this with indexing but I believe there must be a better way. I want to be able to reference the column values by name. Here is that I have:</p>
  
  <pre><code>test_df = DataFrame( A = [1,2,3,4,5], B = [2,3,4,5,6])
  test_df["C"] = [ test_df[i,"A"] * test_df[i,"B"] for i in 1:size(test_df,1)]
  </code></pre>
  
  <p>Is this the Julia/DataFrames way of doing this? Is there a more Julia-eque way of doing this? Thanks for any feedback.</p>