On Tue, 31 Mar 2009, Stephen Weigand wrote:
I wonder if the 'sep' argument in reshape() is being ignored
unintentionally:
## From example(reshape)
df <- data.frame(id=rep(1:4,rep(2,4)),
visit=I(rep(c("Before","After"),4)),
x=rnorm(4), y=runif(4))
reshape(df, timevar="visit", idvar="id", direction="wide", sep = "_")
id x.Before y.Before x.After y.After
1 1 0.773 0.293 -0.021 0.658
3 2 -0.518 0.351 -0.623 0.946
5 3 0.773 0.293 -0.021 0.658
7 4 -0.518 0.351 -0.623 0.946
Is this more of the intended result when 'sep = "_"'?
No. sep= is designed for going the other way. If you have wide-format data with variable names x.Before y.Before x.After y.After, using sep="." will let reshape() work out that the long-format variable names are x and y and the conditions to be put in the time variable are Before and After.
-thomas
Thomas Lumley Assoc. Professor, Biostatistics
tlumley at u.washington.edu University of Washington, Seattle