On Jan 18, 2012, at 4:06 AM, pengcafe wrote:
I have a data frame and I would like to reshape it to wide format
while at
the same time applying different aggregate functions to each column
AND at
times multiple aggregate functions:
test1 = data.frame(
id = c(rep('101',8),rep('102',8)),
phase = rep(c('D','D','L','L'),4),
day = rep(c('1','1','1','1','2','2','2','2'),2),
col1 = c(rep(1,8),rep(2,8)),
col2 = c(runif(8,min=0,max=1),runif(8,min=0,max=10))
)
In this example, I would like to end up with 2 rows (for the 2 ids)
and
different columns for phase-day. Values of col1 should just be
summed and
for col 2 there should be a column with the mean AND one with standard
deviation for each phase-day combination.
Obviously the real data have much more number of columns therefore I
guess I
will need to provide a list of functions?
You should do the reshaping part and the aggregation parts separately
and then merge the two (or three?) results on "id"
--
David Winsemius, MD
West Hartford, CT
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