Here’s a test data which uses plyr‘s transform to calculate the cumulative sum first and then apply that data to plot using ggplot2:
set.seed(45)
DF <- data.frame(grp = factor(rep(1:5, each=10)), x=rep(1:10, 5))
DF <- transform(DF, y=runif(nrow(DF)))
# use plyr to calculate cumsum per group of x
require(plyr)
DF.t <- ddply(DF, .(grp), transform, cy = cumsum(y))
# plot
require(ggplot2)
ggplot(DF.t, aes(x=x, y=cy, colour=grp, group=grp)) + geom_line()Read more here: Source link
