title: Pandas: find if a column name exists in excel sheet?
body: <p>Using pandas:
  I am reading 1 excel sheet &amp; gathering data from it, to then create a new excel document.</p>
  <p>The code I have only works if the user chooses an excel sheet that has the exact, specific string name for the column. I need to be able to check if the column name exists in the excel sheet. What I have now:</p>
  <pre><code>db = pandas.read_excel(full_path_with_file_name, sheetname=sheet_name)
  list_values = db['column_name'].values
  </code></pre>
  <p>I grab that list of values and use it with xlsxwriter.</p>
  <p>I would like to first check that the column EXISTS in excel before I gather the values from that column. If the column does not exist, I would just like to simply assign &quot;unknown&quot; as the value for the new xlsx.</p>
  <p>I've tried various forms of:</p>
  <pre><code>if db['column_names']:
       list_values = db['column_name'].values
  else:
       list_values = # just 'unknown' or 'not found' 
  </code></pre>
  <p>Or some such version of that.</p>
  <p>How to properly check that an excel column name exists?</p>