downSample will randomly sample a data set so that all classes have
the same frequency as the minority class. upSample samples with
replacement to make the class distributions equal
downSample(x, y, list = FALSE, yname = "Class")a matrix or data frame of predictor variables
a factor variable with the class memberships
should the function return list(x, y) or bind x
and y together? If FALSE, the output will be coerced to a data
frame.
if list = FALSE, a label for the class column
Either a data frame or a list with elements x and y.
Simple random sampling is used to down-sample for the majority class(es). Note that the minority class data are left intact and that the samples will be re-ordered in the down-sampled version.
For up-sampling, all the original data are left intact and additional samples are added to the minority classes with replacement.
# NOT RUN {
## A ridiculous example...
data(oil)
table(oilType)
downSample(fattyAcids, oilType)
upSample(fattyAcids, oilType)
# }