[R] reshape a wide data frame from wide to a long format with metadata columns

[ALAN SMITH]

Hello R users and developers,
I have a general question about reshaping a wide data frame using the
"reshape" command. I have a data frame consisting of 108 columns that
I would like to convert to a long table and remove the metadata
(embedded in the column names of the wide table) to new metadata
columns in the long format.

#example data frame. NOTE column names contain metadata::
mediacont.21.MC1A contains  treatment=mediacont, time=21, rep=MC1A

data1<-data.frame(cbind(name=0:10,
mediacont.21.MC1A=10:20,mediatreat.20.MD1A=30:40,
treat.20.T2C=50:60,treat.20.T2A=70:80,condtp.20.C2A=90:100,condtp.20.C2B=100:110,
mediacont.21.MC1B=120:130, mediacont.21.MC1B=130:140))

#example of reshape code that works, this creates a data frame with
single metadata column and unique ID column. I could use this and
create a loop to write metadata columns based on the metadata in the
time column.  However if I understand from reading the reshape command
it can create new metadata columns based on the names of the columns
in wide format.  I  used the "." as a separator between metadata.

data2<- reshape(data1, idvar="name", direction="long",
varying=c(names(data1[-1])), v.names="intensity",
times=names(data1[-1]),sep=".")


## this code does not work, but I think I need something like this.
data3<- reshape(data1, idvar="name", direction="long",
varying=c(names(data1[-1])),sep=".",
v.names=list(c("treat","time","rep", "intensity")))


Could someone please offer me some scripting advise on how to reshape
the dataframe from wide
into long format and split the metadata out of the column names. sep="."

I am trying to create a table with a header like this
"name", "treat", "time", "rep", "original column name", "intensity"

Thank you,
Alan