R/subset.R

In ssdtools: Species Sensitivity Distributions

#    Copyright 2021 Environment and Climate Change Canada
#
#    Licensed under the Apache License, Version 2.0 (the "License");
#    you may not use this file except in compliance with the License.
#    You may obtain a copy of the License at
#
#       https://www.apache.org/licenses/LICENSE-2.0
#
#    Unless required by applicable law or agreed to in writing, software
#    distributed under the License is distributed on an "AS IS" BASIS,
#    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
#    See the License for the specific language governing permissions and
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#' Subset fitdists Object
#'
#' Select a subset of distributions from a fitdists object.
#' The Akaike Information-theoretic Criterion differences are calculated after
#' selecting the distributions named in select.
#' 
#' @inheritParams params
#' @export
#' @examples
#' fits <- ssd_fit_dists(ssddata::ccme_boron)
#' subset(fits, c("gamma", "lnorm"))
subset.fitdists <- function(x, select = names(x), delta = Inf, ...) {
  if(!length(x)) return(x)
  
  chk_s3_class(select, "character")
  chk_vector(select)
  chk_unique(select)
  chk_number(delta)
  chk_gte(delta)
  chk_named(x)
  chk_superset(names(x), select)

  chk_unused(...)

  attrs <- .attrs_fitdists(x)

  class <- class(x)
  x <- x[names(x) %in% select]
  
  class(x) <- class
  .attrs_fitdists(x) <- attrs
  
  if(!length(x)) return(x)
  
  d <- glance(x)$delta
  x <- x[is.na(d) | abs(d) <= delta]
  
  class(x) <- class
  .attrs_fitdists(x) <- attrs
  
  x
}