> -----Original Message----- > From: r-help-boun...@r-project.org [mailto:r-help-bounces@r- > project.org] On Behalf Of Rich Shepard > Sent: Thursday, October 27, 2011 8:26 AM > To: r-help@r-project.org > Subject: [R] Syntax Check: rshape2 melt() > > > This is my first excursion into using reshape2 and I want to ensure > that > the melt() function call is syntactically correct. > > The unmodifed data frame is organized this way: > > head(tds.anal) > site sampdate param quant > 1 UDS-O 2006-12-06 TDS 10800 > 4 STC-FS 1996-06-14 Cond 280 > 7 UDS-O 2007-10-04 Mg 1620 > 9 UDS-O 2007-10-04 SO4 7580 > 19 JCM-10B 2007-06-21 Ca 79 > 20 JCM-10B 2007-06-21 Cl 114 > > What I want looks like this: > > site sampdate TDS Cond Mg Ca Cl Na SO4 > UDS-O 2006-12-06 10800 NA 1620 NA NA NA 7580 > > with the actual data for each param, of course. > > I've read the reshape.pdf, reshape2.pdf, the ?melt help page, and > the > ?melt.data.frame help page. I'm still unclear on the differences among > measure.vars, variable.name, and value.name. After several attempts I > have > what may be what the melted tds.anal should look like: > > m.tds.anal <- melt(tds.anal, id.vars = c('site', 'sampdate', 'param'), > \ > measure.vars = 'quant', value.name = 'quant', na.rm = F) > > head(m.tds.anal) > site sampdate param variable quant > 1 UDS-O 2006-12-06 TDS quant 10800 > 2 STC-FS 1996-06-14 Cond quant 280 > 3 UDS-O 2007-10-04 Mg quant 1620 > 4 UDS-O 2007-10-04 SO4 quant 7580 > 5 JCM-10B 2007-06-21 Ca quant 79 > 6 JCM-10B 2007-06-21 Cl quant 114 > > Is the melt() function call correct? Should the melted result look > like > the unmelted ("long" form in Paul Dalgaard's book) data with the > additional > 'variable' column containing 'quant' for each row? > > Rich >
Rich, What I think you want is as simple as test.melted <- melt(test) wanted <- cast(test.melted, site + sampdate ~ param) Hope this is helpful, Dan Daniel J. Nordlund Washington State Department of Social and Health Services Planning, Performance, and Accountability Research and Data Analysis Division Olympia, WA 98504-5204 ______________________________________________ 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.
