[R] reshape

[nrm2010]

Hello, helpeRs,

I am attempting to reshape (either base R or package reshape) multiple .csv 
spreadsheets from a very unfortunate wide format to long format.  Each spreadsheet 
looks something like this, after being read in to R:

toy <- data.frame(year = rep(2007:2008,each = 20), month = rep(1:5,each = 4, length = 40), 
day = rep(1:2,each = 2,length = 40), hhmm = rep(1100:1101,length = 40), plot = rep(1,40), 
trt=rep(4,40), VWC.B1 = rnorm(40), VWC.B2 = rnorm(40), VWC.T1 = rnorm(40), 
VWC.T2 = rnorm(40), VWC.T10 = rnorm(40), Tair.B1 = rnorm(40),Tair.B2 = rnorm(40), 
Tair.T1 =  rnorm(40), Tair.T2 = rnorm(40))

Taken together, the columns year, month, day, and hhmm define a timepoint
at which at a measurement was taken.  Plot and treatment do not change within
any one spreadsheet.  Parsing the column names, VWC and Tair are 2 different 
types of measurements; in the full dataset, there are more than 2 types of 
measurements.  The B and T in the column names are grouping variables.  The
numbers following the B or T are subjects within groups.  So, if a column name
is VWC.B1, it is the VWC measurement taken on subject 1 within group B. 

I am trying to reshape to long format. The long format should have one new column
for each measurement type (VWC and Tair in the toy example), a new column
indicating the grouping variable (B or T), and a new column identifyng the 
subject (the number that follow the B or T). I've been unable to come up with
a solution that produces the group and subject within group columns as well 
as both types of measurements.

Any assistance would be greatly appreciated.

Thank you.

Toby

Toby Gass, Ph.D.
Visiting Lecturer, Forestry and Wildland Resources
Humboldt State University
email: toby.gass <at> humboldt <dot> edu