I'm constructing a data.table from two (or more) input vectors with different lengths:
x <- c(1,2,3,4)
y <- c(8,9)
dt <- data.table(x = x, y = y)
And need the shorter vector(s) to be filled with NA rather than recycling their values, resulting in a data.table like this:
x y
1: 1 8
2: 2 9
3: 3 NA
4: 4 NA
Is there a way to achieve this without explicitly filling the shorter vector(s) with NA before passing them to the data.table() constructor?
Thanks!
One can use out of range indices:
library("data.table")
x <- c(1,2,3,4)
y <- c(8,9)
n <- max(length(x), length(y))
dt <- data.table(x = x[1:n], y = y[1:n])
# > dt
# x y
# 1: 1 8
# 2: 2 9
# 3: 3 NA
# 4: 4 NA
Or you can extend y by doing (as @Roland recommended in the comment):
length(y) <- length(x) <- max(length(x), length(y))
dt <- data.table(x, y)