Concatenate columns and add them to beginning of Data Frame

Question

Noob here to R. Trying to figure something out. I need to build a function that adds a new column to the beginning of a dataset. This new column is a concatenation of the va

Answer 1

paste0 works fine, with some help from do.call:

do.call(paste0, mydf[c(1, 3, 4)])
# [1] "bat1a" "cow2b" "dog3c"

Your function, thus, can be something like:

addPrimaryKey <- function(inDF, cols) {
  cbind(ID = do.call(paste0, inDF[cols]),
        inDF)
}

You may also want to look at interaction:

interaction(mydf[c(1, 3, 4)], drop=TRUE)
# [1] bat.1.a cow.2.b dog.3.c
# Levels: bat.1.a cow.2.b dog.3.c