---- Original message ---- >Date: Thu, 20 Nov 2008 09:41:11 +0100 >From: "David Hajage" <[EMAIL PROTECTED]> >Subject: Re: [R] Elegant way to transform dataframe? >To: "Barry Rountree" <[EMAIL PROTECTED]> > > I suggest you to have a look to the reshape package, > by Hadley Wickham : http://had.co.nz/reshape/ >
That's exactly what I needed -- thanks! A few comments for other people who might be interested in trying it: 1) "reshape" is the name of the package, "melt" and "cast" are the commands. There's a "reshape" command that's part of the stats package and it does something similar, but it's not nearly so general. 2) I didn't find the package documentation helpful, but the website has links to several papers that provide much better examples. 3) The package requires an up-to-date version of R. I had been using an old version and trying to install the package gave a "not found" error. It wasn't until I downloaded the package and tried a local install that I got a useful error message about the version mismatch. Thanks again, Barry > 2008/11/20 Barry Rountree <[EMAIL PROTECTED]> > > Hello, > > I have a dataframe with columns like: > > parameter1 parameter2 metricname value > > and I'd like to transform it into a dataframe with > columns: > > parameter1 parameter2 metric1 metric2 metric3 > > where the values for each metric would be in the > appropriate column. There are often multiple > values for a given (parameter1, parameter2, > metricname) triple. In this case, I want to use > the minimum value. > > A constant number of metrics is associated with > each possible combination of parameters. > > I've cobbled together code that performs this > using nested loops and far too many variables. > The number of metrics has now gone up by an order > of magnitude and I'm looking for a more elegant > way of doing this. > > If anyone has a short bit of code that can deal > with this, I'd really appreciate having a look. > > Thanks much, > > Barry > > ______________________________________________ > 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.
