Hi, I have a couple of aggregation operations that I don't know how to accomplish. Let me give an example. I have the following irregular time series
time x 10:00:00.021 20 10:00:00.224 20 10:00:01.002 19 10:00:02:948 20 1) For each entry time, I'd like to get sum of x for the next 2 seconds (excluding itself). Using the above example, the output should be time sumx 10:00:00.021 39 10:00:00.224 19 10:00:01.442 20 10:00:02:948 0 2) For each i-th of x in the series, what's the first passage time to x[i]-1. I.e. the output should be time firstPassgeTime 10:00:00.021 0.981 10:00:00.224 0.778 10:00:01.442 NA 10:00:02:948 NA Is there any shortcut function that allows me to do the above? Thank you. adschai ______________________________________________ R-help@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.