Sorry if this is a basic question. I'm using R 3.0.0 and data.table 1.8.8. The documentation for 'j' states that "A single column or single _expression_ returns that type, usually a vector." I am able to obtain this behavior if I know the column name in advance: > dt = data.table(a=c(1, 2, 3), b=c(4, 5, 6)) > dt a b 1: 1 4 2: 2 5 3: 3 6 > str(dt[,a]) num [1:3] 1 2 3 However, if I don't, no such luck: > colname="a" > str(dt[,colname,with=F]) Classes ‘data.table’ and 'data.frame': 3 obs. of 1 variable: $ a: num 1 2 3 - attr(*, ".internal.selfref")=<externalptr> If there a way to extract an entire column as a vector if I have the column name as a character scalar? Thank you! -- Alexandre Sieira CISA, CISSP, ISO 27001 Lead Auditor "The truth is rarely pure and never simple." Oscar Wilde, The Importance of Being Earnest, 1895, Act I |
_______________________________________________ datatable-help mailing list [email protected] https://lists.r-forge.r-project.org/cgi-bin/mailman/listinfo/datatable-help
