BUG: Improve error message for unsupported datetime and timedelta dty…

…pes in cov()
pandas-dev · mroeschke · May 23, 2025 · Feb 9, 2025 · Feb 9, 2025 · Mar 9, 2025
commit cff4f369af762b5adf1dca2a08d6f96f6c7dcbec
diff --git a/pandas/core/frame.py b/pandas/core/frame.py
@@ -105,6 +105,8 @@
    is_sequence,
    needs_i8_conversion,
    pandas_dtype,
+    is_timedelta64_dtype,
+    is_datetime64_any_dtype,
 )
 from pandas.core.dtypes.concat import concat_compat
 from pandas.core.dtypes.dtypes import (
@@ -11267,10 +11269,11 @@ def cov(
        c -0.150812  0.191417  0.895202
        """
        data = self._get_numeric_data() if numeric_only else self
-        if data.select_dtypes(include=[np.datetime64, np.timedelta64]).shape[1] > 0:
+        dtypes = [blk.dtype for blk in self._mgr.blocks]
+        if any(is_datetime64_any_dtype(d) or is_timedelta64_dtype(d) for d in dtypes):
            msg = (
-                "DataFrame contains columns with dtype datetime64[ns] "
-                "or timedelta64[ns], which are not supported for cov."
+                "DataFrame contains columns with dtype datetime64 "
+                "or timedelta64, which are not supported for cov."
            )
            raise TypeError(msg)
        cols = data.columns