Reshape Data Long to Wide - understanding reshape parameters

Question

I have a long format dataframe dogs that I\'m trying to reformat to wide using the reshape() function. It currently looks like so:

dogid  month  year  traini         


        

Answer 1

In this case, using base reshape, you essentially want an interaction() of the three time variables to define your wide variables, so:

idvars  <- c("dogid","home","school")
grpvars <- c("year","month","trainingtype")
outvar  <- "timeincomp"
time    <- interaction(dat[grpvars])

reshape(
  cbind(dat[c(idvars,outvar)],time),
  idvar=idvars,
  timevar="time",
  direction="wide"
)

#  dogid home school timeincomp.2014.1.1 timeincomp.2014.2.1 timeincomp.2015.12.2
#1 12345    1      1                 340                 360                   NA
#3 31323    7      3                 500                 520                  440