Dear all R users, I am going to use R to process some of my physiological data about eye.
The problem is the recording machine does not sample in a reliably constant rate: the time intervals between data sampled can vary from 9msec to ~120msec, while most around in the 15-30msec range. The below is a fraction of a single data file of a trial: Time CursorX CursorY Pupilsize 1811543 -1 -1 -1 1811563 -1 -1 -1 1811584 511 370 4.175665 1811603 511 368 4.181973 1811624 521 368 4.210732 1811644 512 377 4.149632 1811664 524 377 4.275845 1811684 518 368 4.236212 1811703 516 370 4.238384 1811725 507 364 4.181157 1811744 509 371 4.185016 1811764 509 377 4.231987 1811784 514 387 4.252449 1811802 515 388 4.273726 My goal is to "resample" these data so that the "Time" column increments by a regular interval, and the other columns of data are the averages (or estimates) at the point in time according to available data points. I have done something that I use a regular interval that is larger than the naturally occurring record machine, i.e. > 120msec for example, and acquire an average of the available data points for any particular regular time interval. Now, I need to achieve resampling for smaller regular interval: i.e. 5msec intervals, and interpolate / intrapolate the missing data points from the available ones. i.e. I may have to split up data points into the number of the regular intervals that it may occupied in time. Do you know if there is any package that is doing something similar? And because of the size of the data and computational demand (1500 files each with 2000-8000+ lines), can you suggest me some (algorithmically) more efficient way of doing this? Thanks a lot! Regards, John ______________________________________________ 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.