Move a column to first position in a data frame

Question

I would like to have the last column of the data frame moved to the start (as first column). How can I do it in R?

My data.frame has about a thousand columns to chan

Answer 1

A native R approach that works with any number of rows or columns to move the last column of a dataframe to the first column position:

df <- df[,c(ncol(df),1:ncol(df)-1)]

It can be used to move any column to the first column by replacing:

df <- df[,c(your_column_number_here,1:ncol(df)-1)]

If you don't know the column number, but know the column label name, do the following replacing "your_column_name_here":

columnNumber <- which(colnames(df)=="your_column_name_here")
df <- df[,c(columnNumber,1:ncol(df)-1)]