Connecting across missing values with geom_line

Question

I\'m trying to figure out if it\'s possible to connect across missing values using geom_line. For example, in the link below there are missing values at time 3 in facet F. I

Answer 1

Richie's answer is very thorough, but I wanted to show something simpler. Since lines are not drawn to NA points, another approach is drop these points when drawing lines. This implicitly makes a linear interpolation between points (as straight lines do).

Using dfr from Richie's answer, without needing the calculation of z step:

ggplot(dfr, aes(x,y)) + 
  geom_point() +
  geom_line(data=dfr[!is.na(dfr$y),])

For that matter, in this case the subsetting could be done for the whole thing.

ggplot(dfr[!is.na(dfr$y),], aes(x,y)) + 
  geom_point() +
  geom_line()