data(simdat)
(test <- simdat[1:20,])
test$Y.prev <- move_n_point(test$Y)
test$change <- test$Y - test$Y.prev
test$Y.post5 <- move_n_point(test$Y, n=-5)
emptyPlot(nrow(test), range(test$Y))
lines(test$Y)
lines(test$Y.prev, col='red')
lines(test$Y.post5, col='blue')
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