Re: [Rd] corrupt data frame: columns will be truncated or padded with NAs in:, digits = digits)

From: Gregor GORJANC <>
Date: Mon 14 Feb 2005 - 23:32:04 EST


Sending this also to r-help so anyone can read it also there and maybe also help me with my puzzle if this trivial and I don't see it.

Prof Brian Ripley wrote:
[... removed some ...]
> You add a column, not replace part of a non-existent column. Isn't that
> obvious, given what you wrote?

# OK. If I do
tmp <- data.frame(y1=1:4, f1=factor(c("A", "B", "C", "D"))) tmp[1:2, "y2"] <- 2
# I am changing nonexistent column y2 in data frame tmp.

# If I do
tmp <- data.frame(y1=1:4, f1=factor(c("A", "B", "C", "D"))) tmp$y2 <- NA
tmp[1:2, "y2"] <- 2
# I am changing existent column. I understand now the difference. However, # it is weird for me that this is OK (if column y2 does not yet exist) tmp["y2"] <- 2
# but this is not
tmp[1:2, "y2"] <- 2

> There is a lot of basic documentation on data manipulation in R/S, and a
> whole chapter in MASS4. Somehow most other people don't seem to find
> this a problem.

I just ordered MASS4 last week and I am eager to get it in my hands. In meanwhile I read quite some documentation and what I more or less saw is

tmp <- data.frame(y1=1:4, f1=factor(c("A", "B", "C", "D"))) tmp$y2 <- 1:4
tmp$y3 <- 2*tmp$y1

i.e. everybody is adding full column to data frame. But I would like to add just one part.

Lep pozdrav / With regards,
     Gregor GORJANC

University of Ljubljana
Biotechnical Faculty       URI:
Zootechnical Department    mail: gregor.gorjanc <at>
Groblje 3                  tel: +386 (0)1 72 17 861
SI-1230 Domzale            fax: +386 (0)1 72 17 888

______________________________________________ mailing list
Received on Mon Feb 14 22:45:27 2005

This archive was generated by hypermail 2.1.8 : Fri 18 Mar 2005 - 09:02:52 EST