Per-variable specification of boolean parameters in open_dataset

xarray/backends/api.py

@@ -398,7 +398,7 @@ def open_dataset(
     chunks: T_Chunks = None,
     cache: bool | None = None,
     decode_cf: bool | None = None,
-    mask_and_scale: bool | None = None,
+    mask_and_scale: bool | dict[str, bool] | None = None,
     decode_times: bool | None = None,
     decode_timedelta: bool | None = None,
     use_cftime: bool | None = None,
@@ -451,14 +451,16 @@ def open_dataset(
     decode_cf : bool, optional
         Whether to decode these variables, assuming they were saved according
         to CF conventions.
-    mask_and_scale : bool, optional
+    mask_and_scale : bool or dict, optional
         If True, replace array values equal to `_FillValue` with NA and scale
         values according to the formula `original_values * scale_factor +
         add_offset`, where `_FillValue`, `scale_factor` and `add_offset` are
         taken from variable attributes (if they exist).  If the `_FillValue` or
         `missing_value` attribute contains multiple values a warning will be
         issued and all array values matching one of the multiple values will
-        be replaced by NA. This keyword may not be supported by all the backends.
+        be replaced by NA. Pass a mapping, e.g. ``{"my_variable": False}``,
+        to toggle this feature per-variable individually.
+        This keyword may not be supported by all the backends.
     decode_times : bool, optional
         If True, decode times encoded in the standard NetCDF datetime format
         into datetime objects. Otherwise, leave them encoded as numbers.

xarray/conventions.py

@@ -384,11 +384,18 @@ def _update_bounds_encoding(variables: T_Variables) -> None:
                     bounds_encoding.setdefault("calendar", encoding["calendar"])
 
 
+def _item_or_default(obj: Mapping | Any, key: Hashable, default: Any = None):
+    """
+    Return item by key if obj is mapping and key is present, else return default value.
+    """
+    return obj.get(key, default) if isinstance(obj, Mapping) else obj
+
+
 def decode_cf_variables(
     variables: T_Variables,
     attributes: T_Attrs,
     concat_characters: bool = True,
-    mask_and_scale: bool = True,
+    mask_and_scale: bool | dict[str, bool] = True,
     decode_times: bool = True,
     decode_coords: bool | Literal["coordinates", "all"] = True,
     drop_variables: T_DropVariables = None,
@@ -441,7 +448,7 @@ def stackable(dim: Hashable) -> bool:
                 k,
                 v,
                 concat_characters=concat_characters,
-                mask_and_scale=mask_and_scale,
+                mask_and_scale=_item_or_default(mask_and_scale, k, True),
                 decode_times=decode_times,
                 stack_char_dim=stack_char_dim,
                 use_cftime=use_cftime,