Fix/duckdb missings (#34)

mlr-org · Oct 17, 2023 · 3ba5812 · 3ba5812
1 parent 0fc64eb
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diff --git a/DESCRIPTION b/DESCRIPTION
@@ -1,6 +1,6 @@
 Package: mlr3db
 Title: Data Base Backend for 'mlr3'
-Version: 0.5.1
+Version: 0.5.1-9000
 Authors@R:
     person(given = "Michel",
            family = "Lang",

diff --git a/NEWS.md b/NEWS.md
@@ -1,3 +1,7 @@
+# mlr3db 0.5.2
+
+- Bugfix: `DataBackendDuckDB` calculated missing values incorrectly
+
 # mlr3db 0.5.1
 
 - Compatibility with new duckdb version (#36).

diff --git a/R/DataBackendDuckDB.R b/R/DataBackendDuckDB.R
@@ -188,7 +188,7 @@ DataBackendDuckDB = R6Class("DataBackendDuckDB", inherit = DataBackend, cloneabl
       )
 
       counts = unlist(DBI::dbGetQuery(private$.data, query), recursive = FALSE)
-      setNames(as.integer(self$nrow - counts), cols)
+      setNames(as.integer(length(rows) - counts), cols)
     }
   ),
 

diff --git a/tests/testthat/test_duckdb.R b/tests/testthat/test_duckdb.R
@@ -62,3 +62,10 @@ test_that("multiple parquet file", {
   b = as_duckdb_backend(files)
   expect_backend(b)
 })
+
+test_that("missings are calculated correctly", {
+  d = data.frame(x = c(NA, 1), y = c(1, 1))
+  b = as_duckdb_backend(d, path = tempfile())
+  expect_equal(b$missings(1, "x"), c(x = 1))
+  expect_equal(b$missings(2, "x"), c(x = 0))
+})