BUG: np.loadtxt cannot load text file with quoted fields separated by whitespace (#22906)

Fix issue with `delimiter=None` and quote character not working properly (not using whitespace delimiter mode).

Closes gh-22899

1 files changed, 14 insertions, 0 deletions

diff --git a/numpy/lib/tests/test_loadtxt.py b/numpy/lib/tests/test_loadtxt.py
index 819a8dda4..8a5b044b8 100644
--- a/numpy/lib/tests/test_loadtxt.py
+++ b/numpy/lib/tests/test_loadtxt.py
@@ -534,6 +534,20 @@ def test_quoted_field(q):
     assert_array_equal(res, expected)
 
 
+@pytest.mark.parametrize("q", ('"', "'", "`"))
+def test_quoted_field_with_whitepace_delimiter(q):
+    txt = StringIO(
+        f"{q}alpha, x{q}     2.5\n{q}beta, y{q} 4.5\n{q}gamma, z{q}   5.0\n"
+    )
+    dtype = np.dtype([('f0', 'U8'), ('f1', np.float64)])
+    expected = np.array(
+        [("alpha, x", 2.5), ("beta, y", 4.5), ("gamma, z", 5.0)], dtype=dtype
+    )
+
+    res = np.loadtxt(txt, dtype=dtype, delimiter=None, quotechar=q)
+    assert_array_equal(res, expected)
+
+
 def test_quote_support_default():
     """Support for quoted fields is disabled by default."""
     txt = StringIO('"lat,long", 45, 30\n')