[datatable-help] .SD without by seems to fail

[Joseph Voelkel]

# from  help(data.table)
DT = data.table(x=rep(c("a","b","c"),each=3), y=c(1,3,6), v=1:9)
DT[,lapply(.SD,sum),by=x]  # this works fine

# but this fails
DT[,lapply(.SD,sum)]
# with this message: Error in lapply(.SD, sum) : object '.SD' not found

# Am I missing something obvious here?

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