DEPS: Update NumpyExtensionArray repr for NEP51

Author: rhshadrach

pandas/core/arrays/numpy_.py

@@ -2,6 +2,7 @@
 
 from typing import (
     TYPE_CHECKING,
+    Any,
     Literal,
 )
 
@@ -29,6 +30,8 @@
 from pandas.core.strings.object_array import ObjectStringArrayMixin
 
 if TYPE_CHECKING:
+    from collections.abc import Callable
+
     from pandas._typing import (
         AxisInt,
         Dtype,
@@ -565,3 +568,10 @@ def _wrap_ndarray_result(self, result: np.ndarray):
 
             return TimedeltaArray._simple_new(result, dtype=result.dtype)
         return type(self)(result)
+
+    def _formatter(self, boxed: bool = False) -> Callable[[Any], str | None]:
+        # NEP 51: https://github.com/numpy/numpy/pull/22449
+        if self.dtype == "object":
+            return repr
+        else:
+            return str

pandas/tests/arrays/numpy_/test_numpy.py

@@ -323,3 +323,30 @@ def test_factorize_unsigned():
     tm.assert_numpy_array_equal(res_codes, exp_codes)
 
     tm.assert_extension_array_equal(res_unique, NumpyExtensionArray(exp_unique))
+
+
+# ----------------------------------------------------------------------------
+# Output formatting
+
+
+def test_array_repr(any_numpy_array):
+    # GH#???
+    nparray = any_numpy_array
+    arr = NumpyExtensionArray(nparray)
+    if nparray.dtype == "object":
+        values = "['a', 'b']"
+    elif nparray.dtype == "float64":
+        values = "[0.0, 1.0]"
+    elif nparray.dtype == "int64":
+        values = "[0, 1]"
+    elif nparray.dtype == "complex128":
+        values = "[0j, (1+2j)]"
+    elif nparray.dtype == "bool":
+        values = "[True, False]"
+    elif nparray.dtype == "datetime64[ns]":
+        values = "[1970-01-01T00:00:00.000000000, 1970-01-01T00:00:00.000000001]"
+    elif nparray.dtype == "timedelta64[ns]":
+        values = "[0 nanoseconds, 1 nanoseconds]"
+    expected = f"<NumpyExtensionArray>\n{values}\nLength: 2, dtype: {nparray.dtype}"
+    result = repr(arr)
+    assert result == expected

pandas/tests/arrays/test_period.py

@@ -181,4 +181,5 @@ def test_repr_large():
         "'2001-01-01']\n"
         "Length: 1000, dtype: period[D]"
     )
+    print(result)
     assert result == expected