title: Find if a value exists in a column in Excel using python
body: <p>I have an Excel file with one worksheet that has sediment collection data. I am running a long Python script. </p>
  
  <p>In the worksheet is a column titled “CollectionYear.” Say I want the year 2010. If the year 2010 exists in the “CollectionYear” column, I want the rest of the script to run, if not then I want the script to stop.</p>
  
  <p>This seems like an easy enough task but for the life of me I cannot figure it out nor find any examples. </p>
  
  <p>Any help would be greatly appreciated.</p>