title: QtableWidget: How to find value in specific column
body: <p>I need to check wether a specific value is in a specific column using qtablewidget.
  In my case I need to check the first column wether an ID is allready existing, if yes I need the number of the containing row to update this row otherwise I like to add the row. 
  Is there any solution provided by QT to check the column or shou </p>