The reshape function and even more powerful reshape package will probably do what you want.
-- Gregory (Greg) L. Snow Ph.D. Statistical Data Center Intermountain Healthcare [EMAIL PROTECTED] (801) 408-8111 > -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On Behalf Of Tom Backer Johnsen > Sent: Tuesday, June 10, 2008 2:59 PM > To: [EMAIL PROTECTED] > Subject: [R] Frame from long to wide format > > I have this frame in the long format which I want to convert > to wide format. There are three columns in the frame, the id > for the rows in the wide format, the name of the column where > the final value (the third > column) is to be placed. > > The complicating factor is that the long format is not > complete in at least two ways, (a) there may be more than one > reference to one cell in the wide format, in that case I want > to use the last one, and (b) there may be no references to a > cell in the wide format, and in that case I want the cell to be an NA. > > I have looked at and done some experiments with the unstack > () function, this does not seem to do what I want. For > instance, if there are more than one reference to a cell in > the wide format, an extra row may be added or a list > structure is produced. > > What I want is to generate a frame in a "loose" manner, more > or less by the generation of a frame with the number of rows > corresponding to the individuals (unique values) and columns > (also unique values). If there are no references in the long > format to a given cell, then the value should be NA, if there > are more than one, the last one should be used. > > I can see (I think) how I could program this by the > generation of a frame with the correct row and column names, > fill that with NA's, and then use a for loop to assign a > value for the long format to the correct cell in the frame. > That is not elegant, but would work. Is it possible to be > pointed towards alternatives? > > ______________________________________________ > R-help@r-project.org mailing list > 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. > ______________________________________________ R-help@r-project.org mailing list 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.
