Add test for reverse_items (#1122)

* Add test for `reverse_items`

* add tests

* fix

* reverse_items for PCA and FA

* save attr

* tests

* remove `reverse_item`

* rd

* rd

Author: strengejacke

DESCRIPTION

@@ -1,7 +1,7 @@
 Type: Package
 Package: parameters
 Title: Processing of Model Parameters
-Version: 0.26.0.10
+Version: 0.26.0.11
 Authors@R:
     c(person(given = "Daniel",
              family = "Lüdecke",

NEWS.md

@@ -23,10 +23,6 @@
 * New function `factor_scores()` to extract factor scores from EFA (`psych::fa()`
   or `factor_analysis()`).
 
-* `get_scores()` gets a `reverse_items` argument, to reverse the scale of
-  items before calculating the sum scores of subscales. This is useful
-  when the items are not coded in the same direction.
-
 * Added and/or improved print-methods for all functions around PCA, FA and Omega.
 
 * Improved efficiency in `model_parameters()` for models from packages *brms*

R/principal_components.R

@@ -322,6 +322,8 @@ principal_components.data.frame <- function(x,
     )
 
     attr(pca_loadings, "data") <- data_name
+    attr(pca_loadings, "dataset") <- original_data
+
     return(pca_loadings)
   }
 

R/utils_pca_efa.R

@@ -13,10 +13,6 @@
 #' observation, else, the sum score of all (sub) items is calculated. If `NULL`,
 #' the value is chosen to match half of the number of columns in a data frame,
 #' i.e. no more than 50% missing values are allowed.
-#' @param reverse_items Character vector of variable names or numeric indices
-#' indicating their column positions in `x` that should be reversed before
-#' computing sum scores. This is useful when the items are not coded in the same
-#' direction. If `NULL` (default), no items are reversed.
 #'
 #' @details
 #' `get_scores()` takes the results from [`principal_components()`] or
@@ -51,23 +47,10 @@
 #' (mtcars$hp + mtcars$qsec) / 2
 #'
 #' @export
-get_scores <- function(x, n_items = NULL, reverse_items = NULL) {
+get_scores <- function(x, n_items = NULL) {
   subscales <- closest_component(x)
   dataset <- attributes(x)$dataset
 
-  # should some items be reversed?
-  if (!is.null(reverse_items)) {
-    # numeric indices should be replaced by their column names
-    if (is.numeric(reverse_items)) {
-      reverse_items <- colnames(dataset)[reverse_items]
-    }
-    if (verbose) {
-      insight::format_message("Reversing items: ", toString(reverse_items))
-    }
-    # reverse the items
-    dataset <- datawizard::reverse_scale(dataset, reverse_items, verbose = verbose)
-  }
-
   out <- lapply(sort(unique(subscales)), function(.subscale) {
     columns <- names(subscales)[subscales == .subscale]
     items <- dataset[columns]

man/get_scores.Rd

@@ -2,6 +2,7 @@ skip_on_cran()
 
 test_that("get_scores", {
   skip_if_not_installed("psych")
+  data(mtcars)
   pca <- principal_components(mtcars[, 1:7], n = 2, rotation = "varimax")
   scores <- get_scores(pca)
   expect_equal(head(scores$Component_1), c(38.704, 38.755, 28.194, 58.339, 78.658, 51.064), tolerance = 1e-2)