Fast lead/lag for vectors

Find the "next" or "previous" values in a vector. It has wrapped data.table's shift function.

lead_dt(x, n = 1L, fill = NA)

lag_dt(x, n = 1L, fill = NA)

Arguments

x

A vector

n

a positive integer of length 1, giving the number of positions to lead or lag by. Default uses 1

fill

Value to use for padding when the window goes beyond the input length. Default uses NA

Value

A vector

See also

lead,shift

Examples

lead_dt(1:5)
#> [1]  2  3  4  5 NA
lag_dt(1:5)
#> [1] NA  1  2  3  4
lead_dt(1:5,2)
#> [1]  3  4  5 NA NA
lead_dt(1:5,n = 2,fill = 0)
#> [1] 3 4 5 0 0