绘制日期与累积字符值的关系图

Question

I have the following data set called someDat showing registration date of users:

     dates  users
11/06/2013  alfred
12/06/2013  andrew
12/06/2013  john
15/06/2013  jojo
15/06/2013  jeff
15/06/2013  samson
18/06/2013  dave
18/06/2013  hamsa
19/06/2013  kambua

Now I'd like to plot dates versus cumulative number of users, as shown in the image. I've tried converting the users into factors and then use the function cumsum but its just not giving me the right graph.

usersSum <- cumsum(as.numeric(factor(someDat$users))); usersSum
plot(someDat$date,someDat$users, type= "b")

I can't figure out where I'm going wrong or whether its the right function to use. Any help will be appreciated.

Answer 1

someDat <- read.table(text='     dates  users
11/06/2013  alfred
12/06/2013  andrew
12/06/2013  john
15/06/2013  jojo
15/06/2013  jeff
15/06/2013  samson
18/06/2013  dave
18/06/2013  hamsa
19/06/2013  kambua',header=TRUE)
someDat$cumsum <- 1:nrow(someDat)
someDat$date2 <- as.POSIXct(as.character(someDat$dates),format='%d/%m/%Y')
# as lines (left plot)
plot(someDat[!duplicated(someDat$dates, fromLast=TRUE),c('date2','cumsum')],type='l')
# as steps (right plot, following DWin)
plot(someDat[!duplicated(someDat$dates, fromLast=TRUE),c('date2','cumsum')],type='l')