R: create new column with name coming from variable

Question

I have a dataframe with several columns and would like to add a new column and name it according to a previous variable. For example:

df <- data.frame(\"A         


        

Answer 1

In the context of a data.frame name also taken in a variable this might be helpful.

df <- data.frame("A" = c(1, 2, 3, 4), "B" = c("a", "c", "d", "b") )
Variable<-"C"
dfname<-"df"
df<-within ( assign(dfname  , get(dfname) ),
             assign(Variable, NA          )
           )

Answer 2

Try [ instead of $:

> df[, Variable] <- NA
> df
  A B  C
1 1 a NA
2 2 c NA
3 3 d NA
4 4 b NA