geom_rect on some panels of a facet_wrap

Question

I am trying to get a shaded rectangle on the first three panels in my facet_wrap plot. However, when I use geom_rect for the job, it produces the r

Answer 1

Here is a solution that creates a new data frame with variable and then takes advantage of recycling in aes to generate the rectangle coordinates for each value in variable.

ggplot(dfTemp) +
  geom_rect(
    data=data.frame(variable=factor(1:3)), 
    aes(xmin=as.Date('2011-02-01'), xmax=as.Date('2011-03-01'), ymin=-Inf, ymax=Inf), 
    alpha = 0.5, fill = 'grey') +
  geom_line(aes(x = date, y = value, group = variable, color = factor(variable))) +
  facet_wrap(~variable , scale = 'free', ncol = 2)