Any data that can be seen in netactview connections list can be copied. The best way to do that is to use the right click contextual menu. Other options are the Edit menu or the Ctrl+C shortcut.
The right click menu is most appropriate because it is aware of the column where the context menu was triggered in. Select the lines you are interested in (Ctrl + click or Shift + click for more than one) and use the Copy by 'Column' functionality while having the mouse cursor in that column when you right click.
If you copy entire lines the columns are separated by one space and one tab. You can use the tab as a delimiter when you paste in a spreadsheet program.