Fix and deprecate slicing using comma

Author: ecomodeller

mikeio/dataset/_dataset.py

@@ -679,7 +679,6 @@ def _del_name_attr(self, name: str) -> None:
     @overload
     def __getitem__(self, key: Hashable | int) -> DataArray: ...
 
-    # Mapping is Iterable
     @overload
     def __getitem__(self, key: Iterable[Hashable]) -> "Dataset": ...
 

mikeio/dfs/_dfs0.py

@@ -3,6 +3,7 @@
 from pathlib import Path
 from datetime import datetime, timedelta
 from typing import Any, Sequence
+import warnings
 
 import numpy as np
 import pandas as pd
@@ -188,13 +189,21 @@ def read(
             sel_time_step_str = None
             time_steps = None
             if time is not None:
-                _, time_steps = _valid_timesteps(dfs.FileInfo, time)
+                if isinstance(time, slice) and isinstance(time.start, str):
+                    return ds.sel(time=time)
+                else:
+                    _, time_steps = _valid_timesteps(dfs.FileInfo, time)
 
         if time_steps:
             ds = ds.isel(time=time_steps)
 
         if sel_time_step_str:
             parts = sel_time_step_str.split(",")
+            if len(parts) > 0:
+                warnings.warn(
+                    f'Comma separated time slicing is deprecated use read(time=slice("{parts[0]}", "{parts[1]}")) instead.',
+                    FutureWarning,
+                )
             if len(parts) == 1:
                 parts.append(parts[0])  # end=start
 
@@ -204,7 +213,8 @@ def read(
                 sel = slice(parts[0], None)  # start only
             else:
                 sel = slice(parts[0], parts[1])
-            ds = ds[sel]  # type: ignore
+
+            return ds.sel(time=sel)
 
         return ds
 

tests/test_dfs0.py

@@ -517,8 +517,10 @@ def test_read_non_eq_dfs0_temporal_subset():
     dfs0file = r"tests/testdata/da_diagnostic.dfs0"
 
     dfs = Dfs0(dfs0file)
-    # TODO should this syntax be supported?
-    ds = dfs.read(time="2017-10-27 01:00,2017-10-27 02:00")
+
+    # deprecated
+    with pytest.warns(FutureWarning, match="time=slice"):
+        ds = dfs.read(time="2017-10-27 01:00,2017-10-27 02:00")
 
     assert len(ds.time) == 7