Under-allocation of truelength after subsetting

[renkun-ken]

The allocation behavior seems to be changed. The truelength() is largely reduced after any subsetting. Massive adding columns to the under-allocated data.table in other environment would fail to apply to the original object.

library(data.table)

dt <- data.table(id = 1:1000)
dt[, x := rnorm(.N)]
truelength(dt)
#> [1] 1025

dt1 <- dt[x > 0]
truelength(dt1)
#> [1] 66

[mattdowle]

Thanks. I see the issue. CsubsetDT does the over-allocation inside it at C level. It needs the alloc.col option passing down from R level. Will do.