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
> -----Original Message----- > From: r-help-bounces at r-project.org [mailto:r-help-bounces at r- > project.org] On Behalf Of Rich Shepard > Sent: Thursday, October 27, 2011 8:26 AM > To: r-help at 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
Try this, based on your small example:> tds.a <- read.table(textConnection("+ 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"), header = TRUE, stringsAsFactors = FALSE)> closeAllConnections()# Define param so that all of its levels are represented: tds.a <- within(tds.a, { param = factor(param, levels = c('TDS', 'Cond', 'Mg', 'Ca', 'Cl', 'Na', 'SO4')) sampdate = as.Date(sampdate) } ) library('reshape2') dcast(tds.a, site + sampdate ~ param, value_var = 'quant') # Result: site sampdate TDS Cond Mg Ca Cl SO4 1 JCM-10B 2007-06-21 NA NA NA 79 114 NA 2 STC-FS 1996-06-14 NA 280 NA NA NA NA 3 UDS-O 2006-12-06 10800 NA NA NA NA NA 4 UDS-O 2007-10-04 NA NA 1620 NA NA 7580 HTH, Dennis On Thu, Oct 27, 2011 at 8:26 AM, Rich Shepard <rshepard at appl-ecosys.com> wrote:> ?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 > > ______________________________________________ > R-help at 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. >