Merge pull request #83 from r-lib/bug-in-dummy

fix bug in dummy() for one_hot = FALSE and 2 levels
r-lib · Nov 25, 2024 · 35720dc · 35720dc
2 parents f72feb2 + 183a16e
commit 35720dc
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diff --git a/R/sparse_dummy.R b/R/sparse_dummy.R
@@ -49,7 +49,7 @@ sparse_dummy <- function(x, one_hot = TRUE) {
 
   n_lvls <- length(lvls)
 
-  if (n_lvls == 1) {
+  if (n_lvls == 1 && one_hot) {
     res <- list(rep(1L, length(x)))
     names(res) <- lvls
     return(res)

diff --git a/tests/testthat/test-sparse_dummy.R b/tests/testthat/test-sparse_dummy.R
@@ -127,6 +127,22 @@ test_that("sparse_dummy(one_hot = FALSE) works with single level", {
   )
 })
 
+test_that("sparse_dummy(one_hot = FALSE) works with two levels", {
+  x <- factor(c("a", "b", "a"))
+  exp <- list(
+    b = c(0L, 1L, 0L)
+  )
+
+  res <- sparse_dummy(x, one_hot = FALSE)
+  expect_identical(
+    res,
+    exp
+  )
+
+  expect_true(is.integer(res$b))
+  expect_true(is_sparse_vector(res$b))
+})
+
 test_that("sparse_dummy(one_hot = TRUE) works zero length input", {
   x <- factor(character())
   exp <- structure(list(), names = character(0))