Multiple column assignment using :=(...) with shift() creates list column types in 1.14.3 #5403
Description
Minimal Reprex
The following code works as expected
dt <- data.table(grp = c(1,1,1,2,2,2), x = 1:6)
dt[, x_prev := shift(x = x, type = "lag", n = 1), by = grp]
dt[, x_next := shift(x = x, type = "lead", n = 1), by = grp]
print(dt)
grp x x_prev x_next
<num> <int> <int> <int>
1: 1 1 NA 2
2: 1 2 1 3
3: 1 3 2 NA
4: 2 4 NA 5
5: 2 5 4 6
6: 2 6 5 NA
but when I try to create x_prev and x_next in one fell swoop, the resulting fields are lists of vectors
dt <- data.table(grp = c(1,1,1,2,2,2), x = 1:6)
dt[, `:=`(
x_prev = shift(x = x, type = "lag", n = 1),
x_next = shift(x = x, type = "lead", n = 1)
), by = grp]
print(dt)
grp x x_prev x_next
<num> <int> <list> <list>
1: 1 1 NA, 1, 2,NA, 4, 5 2, 3,NA, 5, 6,NA
2: 1 2 NA, 1, 2,NA, 4, 5 2, 3,NA, 5, 6,NA
3: 1 3 NA, 1, 2,NA, 4, 5 2, 3,NA, 5, 6,NA
4: 2 4 NA, 1, 2,NA, 4, 5 2, 3,NA, 5, 6,NA
5: 2 5 NA, 1, 2,NA, 4, 5 2, 3,NA, 5, 6,NA
6: 2 6 NA, 1, 2,NA, 4, 5 2, 3,NA, 5, 6,NA
The same code works properly on data.table 1.14.2, so this appears to be a bug introduced by 1.14.3.
> sessionInfo()
R version 4.2.0 (2022-04-22)
Platform: x86_64-apple-darwin21.3.0 (64-bit)
Running under: macOS Monterey 12.4
Matrix products: default
LAPACK: /usr/local/Cellar/r/4.2.0/lib/R/lib/libRlapack.dylib
locale:
[1] en_US.UTF-8/en_US.UTF-8/en_US.UTF-8/C/en_US.UTF-8/en_US.UTF-8
attached base packages:
[1] stats graphics grDevices utils datasets methods base
other attached packages:
[1] data.table_1.14.3
loaded via a namespace (and not attached):
[1] compiler_4.2.0 httr_1.4.3 R6_2.5.1 generics_0.1.2 tools_4.2.0 lubridate_1.8.0