Perspective table edit - retrieve the "before edit" value in script

The table’s onEditCellCommit event returns three values; the table row, column and the edited value. I want to log any changes so I need to read the oldValue but that’s not a property of the table edit event.

def runAction(self, event):
    # These three event values can be obtained.
	r = event['row']
	c = event['column']
	v = event['value']

My table binding is JSON format (as advised in Perspective table edit example, please) so I can get any particular field using the syntax id =[r].id.

What is the right way to get the oldValue from the table before it is updated? How do I relplace id in[r].id with the selected column name, event['column']?

Try jython’s built-in getattr() function, like so:

oldv = getattr([r], c)


Thanks, Phil.