Merge pull request #20678 from corneliusroemer/fix/remove-trailing-point

BUG: Remove trailing dec point in dragon4positional

2 files changed, 11 insertions, 3 deletions

diff --git a/numpy/core/src/multiarray/dragon4.c b/numpy/core/src/multiarray/dragon4.c
index ce0293615..5d245b106 100644
--- a/numpy/core/src/multiarray/dragon4.c
+++ b/numpy/core/src/multiarray/dragon4.c
@@ -1809,9 +1809,16 @@ FormatPositional(char *buffer, npy_uint32 bufferSize, BigInt *mantissa,
             pos--;
             numFractionDigits--;
         }
-        if (trim_mode == TrimMode_LeaveOneZero && buffer[pos-1] == '.') {
-            buffer[pos++] = '0';
-            numFractionDigits++;
+        if (buffer[pos-1] == '.') {
+            /* in TrimMode_LeaveOneZero, add trailing 0 back */
+            if (trim_mode == TrimMode_LeaveOneZero){
+                buffer[pos++] = '0';
+                numFractionDigits++;
+            }
+            /* in TrimMode_DptZeros, remove trailing decimal point */
+            else if (trim_mode == TrimMode_DptZeros) {
+                    pos--;
+            }
         }
     }
 
diff --git a/numpy/core/tests/test_scalarprint.py b/numpy/core/tests/test_scalarprint.py
index ee21d4aa5..4deb5a0a4 100644
--- a/numpy/core/tests/test_scalarprint.py
+++ b/numpy/core/tests/test_scalarprint.py
@@ -306,6 +306,7 @@ class TestRealScalars:
             assert_equal(fpos(tp('1.2'), unique=False, precision=4, trim='-'),
                          "1.2" if tp != np.float16 else "1.2002")
             assert_equal(fpos(tp('1.'), trim='-'), "1")
+            assert_equal(fpos(tp('1.001'), precision=1, trim='-'), "1")
 
     @pytest.mark.skipif(not platform.machine().startswith("ppc64"),
                         reason="only applies to ppc float128 values")