tkinter radiobutton

[William Gill]

I am placing radiobuttons in a 4 X 4 matrix (using loops) and keep 
references to them in a 2 dimensional list ( rBtns[r][c] ).  It works 
fine, and I can even make it so only one button per column can be 
selected, by assigning each column to an intVar.  In many languages a 
radiobutton has a property that can be directly read to see if it is 
selected on unselected.  Tkinter radiobuttons don't seem to have any 
such property.  Is there any way to look (via the script not the screen) 
to determine if it is selected?, or can this only be achieved via 
control variables?

Bill