trend plot in lattice

library(lattice)
library(data.table)
library(pipeR)

N <- 1093L
DT <- data.table(time = Sys.time() + sample.int(86400L, N),
                 value = rnorm(N))

DT[ , idx := rank(time) %>>% match(sort(unique(.)))]
lenXTick <- 20L
xAt <- seq(1, nrow(DT), length.out = lenXTick)
xTickLabel <- DT[idx %in% pmax(1L, floor(xAt)), .(time)] %>>% format("%Y-%m-%d")
xyplot(value ~ idx, DT, scales = list(x = list(at = xAt, labels = xTickLabel,
                                               tick.number = lenXTick, rot = 90)))