Insert a new column between two columns
Post date: Apr 2, 2014 8:12:55 AM
If you want to insert a new column after a certain column, here is a convenient function to do so.
For other ideas, refer to this thread.
# ===================================== # Insert a column in a dataframe after # column "abc" or n-th column # ===================================== insertAfter <- function(df,x,colName,newColName) { if (class(colName)=='numeric') { target <- colName } else { target <- which(names(df) == as.character(colName))[1] } if (target==0) { # put x at the first column out <- cbind(x,df) } else { if (target>=ncol(df)) { # just append it to the end out <- cbind(df,x) } else { out <- cbind(df[,1:target,drop=F], data.frame(x), df[,(target+1):ncol(df),drop=F]) } } names(out)[target+1] <- newColName return(out) } # ================================================ # Demo # ================================================ df <- data.frame(a=1:4, b=5:8, c=9:12) x <- data.frame('new'=c(1,0,1,0)) > df a b c 1 1 5 9 2 2 6 10 3 3 7 11 4 4 8 12 > x new 1 1 2 0 3 1 4 0 > insertAfter(df,x,1,"yeehah") a yeehah b c 1 1 1 5 9 2 2 0 6 10 3 3 1 7 11 4 4 0 8 12 > insertAfter(df,x,'a',"yeehah") a yeehah b c 1 1 1 5 9 2 2 0 6 10 3 3 1 7 11 4 4 0 8 12 > insertAfter(df,x,0,"yeehah") yeehah a b c 1 1 1 5 9 2 0 2 6 10 3 1 3 7 11 4 0 4 8 12 > insertAfter(df,x,'c',"yeehah") a b c yeehah 1 1 5 9 1 2 2 6 10 0 3 3 7 11 1 4 4 8 12 0 > insertAfter(df,x,'b',"yeehah") a b yeehah c 1 1 5 1 9 2 2 6 0 10 3 3 7 1 11 4 4 8 0 12 > insertAfter(df,x,3,"yeehah") a b c yeehah 1 1 5 9 1 2 2 6 10 0 3 3 7 11 1 4 4 8 12 0Created by Pretty R at inside-R.org---------