Preserve attributes for "convert_to_na(drop_levels = TRUE)" (#472)

DESCRIPTION

@@ -1,7 +1,7 @@
 Type: Package
 Package: datawizard
 Title: Easy Data Wrangling and Statistical Transformations
-Version: 0.9.0.5
+Version: 0.9.0.6
 Authors@R: c(
     person("Indrajeet", "Patil", , "[email protected]", role = "aut",
            comment = c(ORCID = "0000-0003-1995-6531", Twitter = "@patilindrajeets")),

NEWS.md

@@ -12,6 +12,8 @@ BUG FIXES
 * `to_numeric()` now correctly deals with inversed factor levels when
   `preserve_levels = TRUE`.
 
+* `convert_to_na()` now preserves attributes for factors when `drop_levels = TRUE`.
+
 # datawizard 0.9.0
 
 NEW FUNCTIONS

R/convert_to_na.R

@@ -105,7 +105,11 @@ convert_to_na.factor <- function(x, na = NULL, drop_levels = FALSE, verbose = TR
     # drop unused labels
     value_labels <- attr(x, "labels", exact = TRUE)
     if (is.factor(x) && isTRUE(drop_levels)) {
+      # save label attribute
+      variable_label <- attr(x, "label", exact = TRUE)
       x <- droplevels(x)
+      # droplevels() discards attributes, so we need to re-assign them
+      attr(x, "label") <- variable_label
     }
     attr(x, "labels") <- value_labels[!value_labels %in% na]
   }

tests/testthat/test-attributes.R

@@ -123,6 +123,10 @@ test_that("convert_to_na, attributes preserved", {
   attr(x, "myattri") <- "I'm here"
   x2 <- convert_to_na(x, na = 2, verbose = FALSE)
   expect_identical(attr(x2, "myattri", exact = TRUE), "I'm here")
+  # label attribute is preserved
+  attr(x$Species, "label") <- "Species Variable"
+  x2 <- convert_to_na(x, na = "setosa", drop_levels = TRUE, verbose = FALSE)
+  expect_identical(attributes(x$Species)$label, "Species Variable")
 })