[R] working with values from ranef()

I am fitting a series of models using lmer(). I'd like to be able to manipulate the coefficients generated by ranef() to facilitate comparisons between models, and I can't figure out how to do it. (This is probably old news for most of you, but the problem is that although the ranef() output is in

[R] drawing a line that shifts from solid to broken

I am graphing longitudinal data from three time points. I'd like to draw a solid line from point 1 to point 2, and then a dashed line from point 2 to point 3. It works if I do it in two steps: > first.vector <- c(mean(year1$variable1), mean(year2$variable1)) > second.vector <- c(NA, mean(year2$var