remove dtype from encoding for datetime64/timedelta64 variables to …

…prevent unnecessary casts
pydata · Sep 19, 2023 · 37db2b0 · 37db2b0
1 parent b08a9d8
commit 37db2b0
Showing 1 changed file with 10 additions and 0 deletions.
diff --git a/xarray/coding/times.py b/xarray/coding/times.py
@@ -777,6 +777,11 @@ def encode(self, variable: Variable, name: T_Name = None) -> Variable:
             safe_setitem(attrs, "units", units, name=name)
             safe_setitem(attrs, "calendar", calendar, name=name)
 
+            # drop dtype in encoding if encoded as float64
+            # to prevent unnecessary casts, see GH #1064
+            if np.issubdtype(data.dtype, np.float64):
+                encoding.pop("dtype", None)
+
             return Variable(dims, data, attrs, encoding, fastpath=True)
         else:
             return variable
@@ -810,6 +815,11 @@ def encode(self, variable: Variable, name: T_Name = None) -> Variable:
             data, units = encode_cf_timedelta(data, encoding.pop("units", None))
             safe_setitem(attrs, "units", units, name=name)
 
+            # drop dtype in encoding if encoded as float64
+            # to prevent unnecessary casts, see GH #1064
+            if np.issubdtype(data.dtype, np.float64):
+                encoding.pop("dtype", None)
+
             return Variable(dims, data, attrs, encoding, fastpath=True)
         else:
             return variable