Merge pull request #213 from ecmwf/feature/contants-fieldlist

Feature/contants fieldlist

earthkit/data/arguments/earthkit_types.py

@@ -168,7 +168,17 @@ class IntType(_IntType, NonListMixin):
 
 
 class IntListType(_IntType, ListMixin):
-    pass
+    def cast(self, value):
+        if isinstance(value, str) and "/" in value:
+            bits = value.split("/")
+            if len(bits) == 3 and bits[1].lower() == "to":
+                value = list(range(int(bits[0]), int(bits[2]) + 1, 1))
+
+            elif len(bits) == 5 and bits[1].lower() == "to" and bits[3].lower() == "by":
+                value = list(
+                    range(int(bits[0]), int(bits[2]) + int(bits[4]), int(bits[4]))
+                )
+        return super().cast(value)
 
 
 class IntSingleOrListType(_IntType, SingleOrListMixin):
@@ -194,6 +204,10 @@ class FloatSingleOrListType(_FloatType, SingleOrListMixin):
 
 class _DateType(Type):
     def _format(self, value, format):
+        if format == "datetime.datetime":
+            return value
+        if format == datetime.datetime:
+            return value
         return value.strftime(format)
 
     def include_args(self, decorator, args):

earthkit/data/core/__init__.py

@@ -8,6 +8,7 @@
 
 import logging
 from abc import abstractmethod
+from collections import defaultdict
 
 LOG = logging.getLogger(__name__)
 
@@ -97,6 +98,37 @@ def order_by(self, *args, **kwargs):
         """Reorder the elements of the object."""
         self._not_implemented()
 
+    def unique_values(self, *coords, remapping=None, progress_bar=True):
+        """
+        Given a list of metadata attributes, such as date, param, levels,
+        returns the list of unique values for each attributes
+        """
+        from earthkit.data.core.order import build_remapping
+        from earthkit.data.utils import progress_bar
+
+        assert len(coords)
+        assert all(isinstance(k, str) for k in coords), coords
+
+        remapping = build_remapping(remapping)
+        iterable = self
+
+        if progress_bar:
+            iterable = progress_bar(
+                iterable=self,
+                desc=f"Finding coords in dataset for {coords}",
+            )
+
+        dic = defaultdict(dict)
+        for f in iterable:
+            metadata = remapping(f.metadata)
+            for k in coords:
+                v = metadata(k)
+                dic[k][v] = True
+
+        dic = {k: tuple(values.keys()) for k, values in dic.items()}
+
+        return dic
+
     # @abstractmethod
     # def to_points(self, *args, **kwargs):
     #     self._not_implemented()

earthkit/data/core/metadata.py

@@ -134,10 +134,11 @@ def _get_internal_key(self, key, astype=None, default=None, raise_on_missing=Tru
     def _get_custom_key(self, key, default=None, raise_on_missing=True):
         try:
             if key == DATETIME:
-                return True, self.datetime().get("valid_time")
+                if key not in self:
+                    return True, self.datetime().get("valid_time")
         except Exception as e:
             if not raise_on_missing:
-                return default
+                return True, default
             else:
                 raise KeyError(f"{key}, reason={e}")
         return False, None