flatten should silently drop NULLs.

tidyverse · Dec 29, 2015 · 13ba73a · 13ba73a
1 parent be22add
commit 13ba73a
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Showing 2 changed files with 7 additions and 3 deletions.
diff --git a/src/flatten.c b/src/flatten.c
@@ -19,7 +19,7 @@ SEXP flatten_impl(SEXP x) {
 
   for (int j = 0; j < m; ++j) {
     SEXP x_j = VECTOR_ELT(x, j);
-    if (!Rf_isVector(x_j))
+    if (!Rf_isVector(x_j) && !Rf_isNull(x_j))
       Rf_errorcall(R_NilValue, "Element %i is not a vector (%s)", j + 1, objtype(x_j));
 
     n += Rf_length(x_j);
@@ -70,8 +70,6 @@ SEXP flatten_impl(SEXP x) {
       if (i % 1000 == 0)
         R_CheckUserInterrupt();
     }
-
-
   }
 
 

diff --git a/tests/testthat/test-flatten.R b/tests/testthat/test-flatten.R
@@ -13,6 +13,12 @@ test_that("each second level element becomes first level element", {
   expect_equal(flatten(list(1, 2)), list(1, 2))
 })
 
+test_that("NULLs are silently dropped", {
+  expect_equal(flatten(list(NULL, NULL)), list())
+  expect_equal(flatten(list(NULL, 1)), list(1))
+  expect_equal(flatten(list(1, NULL)), list(1))
+})
+
 test_that("names are preserved", {
   expect_equal(flatten(list(list(x = 1), list(y = 1))), list(x = 1, y = 1))
   expect_equal(flatten(list(list(a = 1, b = 2), 3)), list(a = 1, b = 2, 3))