title: Loop over multiple columns in dataframe
body: <p>I have a dataframe from a CSV file that has 61 columns and 1mil rows. 25 of those columns <code>(Flag_1, Flag_2, ..., Flag_25)</code> have <code>True/False</code> as values for each row of the dataframe.</p>
  
  <p>What I'm trying to do is loop through each column to determine if there is a True for that entire row within those columns, I just need a minimum of one true. If there is a True then a new column, <code>Flag_All</code> will have a True value for that row, if not, then False.</p>
  
  <p>I can use the for loop for a single column like so,</p>
  
  <pre><code>for index, x in data2['FLAG_1'].iteritems() :
      data2['FLAG_ALL'] =  data2['FLAG_1'] == True
  </code></pre>
  
  <p>but can't figure out for multiple columns.  </p>