Add (insert) a column between two columns in a data.frame

Question

I have a data frame that has columns a, b, and c. I\'d like to add a new column d between b and c.

I know I could just add d at the end by using cbind but h

Answer 1

You can reorder the columns with [, or present the columns in the order that you want.

d <- data.frame(a=1:4, b=5:8, c=9:12)
target <- which(names(d) == 'b')[1]
cbind(d[,1:target,drop=F], data.frame(d=12:15), d[,(target+1):length(d),drop=F])

  a b  d  c
1 1 5 12  9
2 2 6 13 10
3 3 7 14 11
4 4 8 15 12