[R] Erase content of dataframe in a single stroke

[Jim Lemon]

Hi Luigi,
Maybe this:

testdf<-data.frame(A=1,B=2,C=3)
> testdf
 A B C
1 1 2 3
toNull<-function(x) return(NULL)
testdf<-sapply(testdf,toNull)

Jim
On Thu, Sep 27, 2018 at 5:29 PM Luigi Marongiu <marongiu.luigi using gmail.com> wrote:
>
> Dear all,
> I would like to erase the content of a dataframe -- but not the
> dataframe itself -- in a simple and fast way.
> At the moment I do that by re-defining the dataframe itself in this way:
>
> > df <- data.frame(A = numeric(),
> +                   B = numeric(),
> +                   C = character())
> > # assign
> > A <- 5
> > B <- 0.6
> > C <- 103
> > # load
> > R <- cbind(A, B, C)
> > df <- rbind(df, R)
> > df
>   A   B   C
> 1 5 0.6 103
> > # erase
> > df <- data.frame(A = numeric(),
> +                  B = numeric(),
> +                  C = character())
> > df
> [1] A B C
> <0 rows> (or 0-length row.names)
> >
>
> Is there a way to erase the content of the dataframe in a simplier
> (acting on all the dataframe at once instead of naming each column
> individually) and nicer (with a specific erasure command instead of
> re-defyining the object itself) way?
>
> Thank you.
> --
> Best regards,
> Luigi
>
> ______________________________________________
> R-help using r-project.org mailing list -- To UNSUBSCRIBE and more, see
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.