Many of the Ch1 examples have code to print values:
coor = mesh.coordinates()
for i in range(len(u_array)):
print 'u(%8g,%8g) = %g \t exact=%g' \
% (coor[i][0], coor[i][1], u_array[i], u_e_array[i] )}
When I run it, I find that the order of the coor array is different from the order of the u_array, so the coordinates don't match up with the right values. I got around this by interpolating x and y to the same space that u is in (interpolation should be exact) and then printing the interpolated coordinates along with u and u_e.
Is there a better way?