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# A CPO that takes a list of expressions and turns them into columns of new data
#
# Since the 'expr' and 'superceding.env' is not very user-friendly, this is wrapped
# by `cpoMakeCols`, see there.
barecpoMakeCols = makeCPO("new.cols", pSS(expr: untyped, superceding.env: untyped, make.factors: logical, add.cols: logical), # nolint
dataformat = "df.all",
properties.adding = c("numerics.sometimes", "factors.sometimes", "ordered.sometimes"),
properties.needed = c("numerics.sometimes", "factors.sometimes", "ordered.sometimes"),
cpo.train = { target },
cpo.retrafo = {
target = control
if (length({badcols = intersect(names(expr), target)})) {
stopf("Columns %s can not be created, since they clash with the Task's target names", collapse(badcols, ", "))
}
if (add.cols && length({badcols = intersect(names(expr), colnames(data))})) {
stopf("Columns %s can not be created, since they clash with the Task's feature names", collapse(badcols, ", "))
}
reserved = "..CPO..RESERVED.."
if (length(target)) {
reserved = target[1]
}
expr[[reserved]] = seq_len(nrow(data))
ret = data.frame(lapply(expr, function(ex) {
val = eval(ex, data, superceding.env)
if (make.factors && (is.character(val) || is.logical(val))) {
factor(val)
} else {
val
}
}), stringsAsFactors = FALSE)
ret = dropNamed(ret, reserved)
if (add.cols) {
cbind(data, ret)
} else {
ret
}
})
#' @title Create Columns from Expressions
#'
#' @template cpo_doc_intro
#'
#' @description
#' Create columns from expressions and the incoming data.
#'
#' When \code{cpoMakeCols} or \code{cpoAddCols} are called as
#' \code{cpoMakeCols( <newcolname> = <expression>, ... )}, a new column
#' with the name \code{<newcolname} containing the result of
#' \code{<expression>} is created. The
#' expressions need to be vectorising R expressions
#' and may refer to any feature columns in the data (excluding the
#' target) and any other values. The names should be valid \code{data.frame}
#' column names and may not clash with the target column name.
#'
#' \code{cpoMakeCols} replaces existing cols by the newly created
#' ones, \code{cpoAddCols} adds them to the data already present.
#'
#' @param ... [any]\cr
#' Expressions of the form \code{colname = expr}. See Examples.
#' @param .make.factors [\code{logical(1)}]\cr
#' Whether to turn resulting \code{logical} and \code{character}
#' columns into \code{factor} columns (which are preferred
#' by \code{mlr}). Default is \code{TRUE}.
#'
#' @section CPOTrained State:
#' The created state is empty.
#'
#' @examples
#' res = pid.task %>>% cpoAddCols(gpi = glucose * pressure * insulin, pm = pregnant * mass)
#' head(getTaskData(res))
#' @template cpo_doc_outro
#' @export
cpoMakeCols = function(..., .make.factors = TRUE) {
mc = match.call()
mc[[1]] = alist
expr = eval.parent(mc)
expr$.make.factors = NULL
superceding.env = parent.frame()
barecpoMakeCols(expr = expr, superceding.env = superceding.env, make.factors = .make.factors, add.cols = FALSE, export = character(0))
}
cpoMakeCols = wrapFauxCPOConstructor(cpoMakeCols) # nolint
registerCPO(cpoMakeCols, "data", "features", "Replace columns by columns generated from expressions")
#' @rdname cpoMakeCols
#' @export
cpoAddCols = function(..., .make.factors = TRUE) {
mc = match.call()
mc[[1]] = alist
expr = eval.parent(mc)
superceding.env = parent.frame()
barecpoMakeCols(expr = expr, superceding.env = superceding.env, make.factors = .make.factors, add.cols = TRUE, export = character(0))
}
cpoAddCols = wrapFauxCPOConstructor(cpoAddCols) # nolint
registerCPO(cpoAddCols, "data", "features", "Add columns generated from expressions")
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