transformBy {doBy} | R Documentation |
Function to make groupwise transformations of data by applying the transform function to subsets of data.
transformBy(formula, data, ...)
formula |
A formula with only a right hand side, see examples below |
data |
A data frame |
... |
Further arguments of the form tag=value |
The ... arguments are tagged vector expressions, which are evaluated in the data frame data. The tags are matched against names(data), and for those that match, the value replace the corresponding variable in data, and the others are appended to data.
The modified value of the dataframe data.
Søren Højsgaard, sorenh@math.aau.dk
orderBy
,
summaryBy
,
splitBy
,
doby.xtabs
,
data(dietox) transformBy(~Pig, data=dietox, minW=min(Weight), maxW=max(Weight), gain=sum(range(Weight)*c(-1,1)))