Good morning RGuru's I have a data frame of 575 columns. I want to extract only those columns that are numeric(double) or integer to do some machine learning with. I have searched the web for a couple of days (off and on) and have not found anything that shows how to do this. Lots of ways to extract rows, but not columns. I have attempted to use "(x == y)" indices extraction method but that threw error that == was for atomic vectors and lists, and I was doing this on a data frame.
My test code is below # a technique to get column classes library(data.table) a <- 1:10 b <- c("a","b","c","d","e","f","g","h","i","j") c <- seq(1.1, .2, length = 10) dt1 <- data.table(a,b,c) str(dt1) col.classes <- sapply(dt1, class) head(col.classes) dt2 <- subset(dt1, typeof = "double" | "numeric") str(dt2) dt2 # not subset dt2 <- dt1[, list(typeof = "double")] str(dt2) class_data <- dt1[,sapply(dt1,is.integer) | sapply(dt1, is.numeric)] class_data sum(class_data) typeof(class_data) names(class_data) str(class_data) Any help is appreciated Carl Sutton CPA [[alternative HTML version deleted]] ______________________________________________ R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.