R/Extract.R

In ropensci/taxlist: Handling Taxonomic Lists

#' @name Extract
#'
#' @title Extract or Replace Parts of taxlist Objects
#'
#' @description
#' Quick access to slots `taxonTraits` and `taxonRelations` within
#' [taxlist-class] objects.
#'
#' @param x Object of class [taxlist-class].
#' @param i Integer or logical vector used as index for access to taxon
#'   concepts, referring to the rows in slot 'taxonRelations'. These indices can
#'   be used to produce a object with a subset of taxon concepts. It is not
#'   recommended to use character values for this index.
#' @param j Integer, logical or character vector used as index for access to
#'   variables in slot 'taxonTraits'. These indices can be used to reduce the
#'   number of variables in the mentioned slot.
#' @param drop A logical value passed to \code{\link[base]{Extract}}.
#' @param name A symbol or character value for the method `$`, corresponding to
#'   a variable either at slot 'taxonTraits' or slot 'taxonRelations'.
#'
#' @return The method `$` retrieves a vector, while `[` retrieves a subset
#' of the input [taxlist-class] object.
#'
#' @author Miguel Alvarez \email{kamapu78@@gmail.com}.
#'
#' @seealso [taxlist-class] \code{\link[taxlist]{subset}}
#'
#' @example examples/Extract.R
#'
#' @rdname Extract
#'
#' @aliases [ [,taxlist-method
#'
#' @exportMethod [
#'
setMethod(
  "[", signature(x = "taxlist"),
  function(x, i, j, drop = FALSE) {
    if (missing(i)) i <- TRUE
    if (missing(j)) j <- TRUE
    # Resolving problems with NAs
    if (is.logical(i)) i[is.na(i)] <- FALSE else i <- na.omit(i)
    if (is.logical(j)) i[is.na(j)] <- FALSE else j <- na.omit(j)
    x@taxonRelations <- x@taxonRelations[i, , drop]
    if (nrow(x@taxonTraits) > 0) {
      ## k <- with(x@taxonTraits, TaxonConceptID %in%
      ##                 x@taxonRelations$TaxonConceptID)
      k <- x@taxonTraits$TaxonConceptID %in%
        x@taxonRelations$TaxonConceptID
      x@taxonTraits <- x@taxonTraits[k, j, drop]
    }
    return(clean(x))
  }
)

#' @rdname Extract
#'
#' @aliases $ $,taxlist-method
#'
#' @exportMethod $
#'
setMethod("$", signature(x = "taxlist"), function(x, name) {
  pos_nms <- c(colnames(x@taxonTraits), colnames(x@taxonRelations))
  if (!name %in% pos_nms) {
    stop(paste(
      "Only variables in slots 'taxonTraits' or",
      "'taxonRelations' can be accessed by '$'"
    ))
  }
  if (!paste(substitute(name)) %in% colnames(x@taxonRelations)) {
    ## x@taxonRelations[[name]] <- with(x@taxonTraits,
    ##         get(name)[match(x@taxonRelations$TaxonConceptID,
    ##                         TaxonConceptID)])
    x@taxonRelations[[name]] <- x@taxonTraits[
      match(
        x@taxonRelations$TaxonConceptID,
        x@taxonTraits$TaxonConceptID
      ), name
    ]
  }
  return(x@taxonRelations[[name]])
})