time series plot with ggplot2 - a simple example

01	meetup <- read.csv('MeetupDates.csv', as.is=T)

02	names(meetup) <- 'Dates'

03	meetup$Dates <- as.Date(meetup$Dates,format='%m/%d/%y')

04	files  <- dir(pattern='DC_useR')

05	bl <- list()

06	for(f in files){

07	bl[[f]] <- read.csv(f, as.is=T)

08	bl[[f]]$Date <- as.Date(bl[[f]]$Date,format='%m/%d/%y')

09

}

10	dat <- Reduce(function(x,y) merge(x,y), bl) # Merge the data frames by Date

11	dat2 <- melt(dat,id=1)

12

13	# Here comes the trick !!

14	f1 <- ggplot(dat2, aes(x=Date,y=value,ymin=0,ymax=value))+facet_grid(variable~., scales='free')

15	f2 <- f1+geom_step(subset=.(variable=='Total.Members'))

16	f3 <- f2+geom_step(subset=.(variable=='Active.Members'))

17	f4 <- f3+geom_linerange(subset=.(variable=='Member.Joins'))

18	f5 <- f4+geom_linerange(subset=.(variable=='RSVPs'))

19	f5+geom_vline(xintercept=meetup$Dates, color='red',alpha=.3)+ylab('')

http://statbandit.wordpress.com/2011/07/29/a-ggplot-trick-to-plot-different-plot-types-in-facets/