Thank you very much. I just would expect that 'as.matrix' would have the same behaviour as 'data.matrix' when all columns in a data frame are numeric. Regards
Alberto On Thursday 14 August 2003 16:41, Liaw, Andy wrote: > If you look at the structure, you'll see: > > x$V4 <- 0 > > str(x) > > `data.frame': 4 obs. of 4 variables: > $ V1: int 1 2 3 4 > $ V2: int 5 6 7 8 > $ V3: int 9 10 11 12 > $ V4: num 0 > > Don't know if this is the intended result. In any case, you're probably > better off using data.matrix, as > > > data.matrix(x) > > V1 V2 V3 V4 > 1 1 5 9 0 > 2 2 6 10 0 > 3 3 7 11 0 > 4 4 8 12 0 > > HTH, > Andy > > > -----Original Message----- > > From: Alberto Murta [mailto:[EMAIL PROTECTED] > > Sent: Thursday, August 14, 2003 12:50 PM > > To: [EMAIL PROTECTED] > > Subject: [R] vectorization question > > > > > > Dear all > > > > I recently noticed the following error when cohercing a > > data.frame into a > > > > matrix: > > > example <- matrix(1:12,4,3) > > > example <- as.data.frame(example) > > > example$V4 <- 0 > > > example > > > > V1 V2 V3 V4 > > 1 1 5 9 0 > > 2 2 6 10 0 > > 3 3 7 11 0 > > 4 4 8 12 0 > > > > > example <- as.matrix(example) > > > > Error in as.matrix.data.frame(example) : dim<- length of dims > > do not match the > > length of object > > > > However, if the column to be added has the right number of > > lines, there's no > > > > error: > > > example <- matrix(1:12,4,3) > > > example <- as.data.frame(example) > > > example$V4 <- rep(0,4) > > > example > > > > V1 V2 V3 V4 > > 1 1 5 9 0 > > 2 2 6 10 0 > > 3 3 7 11 0 > > 4 4 8 12 0 > > > > > example <- as.matrix(example) > > > example > > > > V1 V2 V3 V4 > > 1 1 5 9 0 > > 2 2 6 10 0 > > 3 3 7 11 0 > > 4 4 8 12 0 > > > > Shouldn't it work well both ways? I checked the attributes > > and dims of the > > data frame and they are the same in both cases. Where's the > > difference that > > originates the error message? > > Thanks in advance > > > > Alberto > > > > platform i686-pc-linux-gnu > > arch i686 > > os linux-gnu > > system i686, linux-gnu > > status > > major 1 > > minor 7.1 > > year 2003 > > month 06 > > day 16 > > language R > > > > > > -- > > Alberto G. Murta > > Institute for Agriculture and Fisheries Research (INIAP-IPIMAR) > > Av. Brasilia, 1449-006 Lisboa, Portugal | Phone: +351 > > 213027062 Fax:+351 213015948 | > > http://www.ipimar-iniap.ipimar.pt/pelagicos/ > > > > > > ______________________________________________ > > [EMAIL PROTECTED] mailing list > > https://www.stat.math.ethz.ch/mailman/listinfo> /r-help > > --------------------------------------------------------------------------- >--- Notice: This e-mail message, together with any attachments, contains > information of Merck & Co., Inc. (Whitehouse Station, New Jersey, USA), > and/or its affiliates (which may be known outside the United States as > Merck Frosst, Merck Sharp & Dohme or MSD) that may be confidential, > proprietary copyrighted and/or legally privileged, and is intended solely > for the use of the individual or entity named on this message. If you are > not the intended recipient, and have received this message in error, please > immediately return this by e-mail and then delete it. > > ______________________________________________ > [EMAIL PROTECTED] mailing list > https://www.stat.math.ethz.ch/mailman/listinfo/r-help -- Alberto G. Murta Institute for Agriculture and Fisheries Research (INIAP-IPIMAR) Av. Brasilia, 1449-006 Lisboa, Portugal | Phone: +351 213027062 Fax:+351 213015948 | http://www.ipimar-iniap.ipimar.pt/pelagicos/ ______________________________________________ [EMAIL PROTECTED] mailing list https://www.stat.math.ethz.ch/mailman/listinfo/r-help