On Jan 28, 2011, at 3:07 PM, Ottar Kvindesland wrote:
> Hello all
>
> I have the data frame with this:
>
> ID DATETIME TRN TRN_S
> 1 1192756 2010-06-23 15:39:07 13.420 0.2236667
> 2 1192757 2010-06-23 15:40:07 13.805 0.2300833
> 3 1192758 2010-06-23 15:41:07 13.860 0.2310000
> 4 1192759 2010-06-23 15:42:07 13.750 0.2291667
> 5 1192760 2010-06-23 15:43:07 13.530 0.2255000
> 6 1192761 2010-06-23 15:44:07 13.805 0.2300833
>
> Now, I would like to plot a graph with DATETIME and the accumulated
> TRN_S.
>
> I can run a while loop like this:
>
> accumulated_trns <- 0
> last_value <-length(data$TRN_S)
> while (i < last_value) {
> acc_trns <- acc_trns + data$TRN_S[i]
> data$accumulated_trns[i] <- acc_trns
> i <- i + 1
> }
> data$accumulated_trns[i] <- acc_trns
> plot(data$DATETIME, data$accumulated_trns)
Perhaps:
plot(data$DATETIME, cumsum(data$TRN_S) )
Can probably also be generalized to cumulative sums within IDs using
ave() or tapply().
>
>
> This is slow and demanding on the computer.
>
> There must be a better way to accumulate values! Any suggestion
> greatly
> appreciated.
>
> [[alternative HTML version deleted]]
>
> ______________________________________________
> R-help at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
David Winsemius, MD
West Hartford, CT