ggplot line graph with NA values

Question

I\'m having with trouble with ggplot trying to plot 2 incomplete time series on the same graph where the y data does not have the same values on the x-axis (year) - NAs are

Answer 1

My preferred solution would be to reshape this to long format. Then you only need 1 geom_line call. Especially if you have many series, that's tidier. Same result as LyzandeR's 2nd chart.

library(ggplot2)
library(reshape2)

test2 <- melt(test, id.var='YEAR')
test2 <- na.omit(test2)

ggplot(test2, aes(x=YEAR, y=value, color=variable)) + 
  geom_line() +
  scale_color_manual(values=c('red', 'green')) +

  xlab("Year") + ylab("Percent") +
  scale_x_continuous(limits=c(1935, 1995), breaks = seq(1935, 1995, 5),
                     expand = c(0, 0)) + 
  scale_y_continuous(limits=c(0,50), breaks=seq(0, 50, 10), expand = c(0, 0))

You might consider adding a geom_point() call in addition to the line, so it's clear which points are real values and which are missing. Another advantage to the long format is that additional geoms take just 1 call each, as opposed to 1 per series each.