library(data.table)
tb<-data.table(x=c(1,2), y=c(3,4), z=c(5,6), w=c("a","b"))
tb[w != "b", .(x=sum(x)), by=.(y, zz=z)] #OK
# y zz x
# 1: 3 5 1
tb[, .(x=sum(x)), by=.(y, zz=get("z"))] #OK
# y zz x
# 1: 3 5 1
# 2: 4 6 2
tb[w != "b", .(x=sum(x)), by=.(y, zz=get("z"))] #not OK?!
Just copied my question on stackoverflow:
getfunction usually works without problems in data.table, but I am not able to understand the reason of this bug.(I use R version 3.3.2 and data.table version 1.9.6.)