Closes Bears-R-Us#3206 MultiIndex.levels (Bears-R-Us#3207)

Co-authored-by: Amanda Potts <ajpotts@users.noreply.github.com>

PROTO_tests/tests/index_test.py

@@ -35,13 +35,13 @@ def test_multiindex_creation(self, size):
         # test list generation
         idx = ak.MultiIndex([ak.arange(size), ak.arange(size)])
         assert isinstance(idx, ak.MultiIndex)
-        assert idx.levels == 2
+        assert idx.nlevels == 2
         assert idx.size == size
 
         # test tuple generation
         idx = ak.MultiIndex((ak.arange(size), ak.arange(size)))
         assert isinstance(idx, ak.MultiIndex)
-        assert idx.levels == 2
+        assert idx.nlevels == 2
         assert idx.size == size
 
         with pytest.raises(TypeError):
@@ -50,6 +50,14 @@ def test_multiindex_creation(self, size):
         with pytest.raises(ValueError):
             idx = ak.MultiIndex([ak.arange(size), ak.arange(size - 1)])
 
+    def test_nlevels(self):
+        i = ak.Index([1, 2, 3], name="test")
+        assert i.nlevels == 1
+
+        size = 10
+        m = ak.MultiIndex([ak.arange(size), ak.arange(size) * -1])
+        assert m.nlevels == 2
+
     @pytest.mark.parametrize("size", pytest.prob_size)
     def test_memory_usage(self, size):
         from arkouda.dtypes import BigInt

PROTO_tests/tests/symbol_table_test.py

@@ -475,7 +475,7 @@ def test_multi_index_registration(self, size):
         # assert that the object is registered
         assert reg_name in reg["Objects"]
         # assert that the sym entry name is recorded
-        for x in i.values:
+        for x in i.levels:
             if x.objType == ak.Categorical.objType:
                 assert x.codes.name in reg["Components"]
                 assert x.categories.name in reg["Components"]

arkouda/index.py

@@ -148,6 +148,17 @@ def _dtype_of_list_values(self, lst):
         else:
             raise TypeError("Index Types must match")
 
+    @property
+    def nlevels(self):
+        """
+        Integer number of levels in this Index.
+        An Index will always have 1 level.
+        See Also
+        --------
+        MultiIndex.nlevels
+        """
+        return 1
+
     @property
     def index(self):
         """
@@ -901,36 +912,35 @@ class MultiIndex(Index):
 
     def __init__(
         self,
-        values: Union[list, pdarray, Strings, Categorical],
+        levels: Union[list, pdarray, Strings, Categorical],
         name: Optional[str] = None,
         names: Optional[list[str]] = None,
     ):
         self.registered_name: Optional[str] = None
-        if not (isinstance(values, list) or isinstance(values, tuple)):
+        if not (isinstance(levels, list) or isinstance(levels, tuple)):
             raise TypeError("MultiIndex should be an iterable")
-        self.values = values
+        self.levels = levels
         first = True
         self.names = names
         self.name = name
-        for col in self.values:
+        for col in self.levels:
             # col can be a python int which doesn't have a size attribute
             col_size = col.size if not isinstance(col, int) else 0
             if first:
-                # we are implicitly assuming values contains arkouda types and not python lists
+                # we are implicitly assuming levels contains arkouda types and not python lists
                 # because we are using obj.size/obj.dtype instead of len(obj)/type(obj)
                 # this should be made explict using typechecking
                 self.size = col_size
                 first = False
             else:
                 if col_size != self.size:
                     raise ValueError("All columns in MultiIndex must have same length")
-        self.levels = len(self.values)
 
     def __getitem__(self, key):
         from arkouda.series import Series
 
         if isinstance(key, Series):
-            key = key.values
+            key = key.levels
         return MultiIndex([i[key] for i in self.index])
 
     def __repr__(self):
@@ -952,11 +962,21 @@ def __eq__(self, v):
 
     @property
     def index(self):
-        return self.values
+        return self.levels
+
+    @property
+    def nlevels(self) -> int:
+        """
+        Integer number of levels in this MultiIndex.
+        See Also
+        --------
+        Index.nlevels
+        """
+        return len(self.levels)
 
     def memory_usage(self, unit="B"):
         """
-        Return the memory usage of the MultiIndex values.
+        Return the memory usage of the MultiIndex levels.
 
         Parameters
         ----------
@@ -988,7 +1008,7 @@ def memory_usage(self, unit="B"):
         from arkouda.util import convert_bytes
 
         nbytes = 0
-        for item in self.values:
+        for item in self.levels:
             nbytes += item.nbytes
 
         return convert_bytes(nbytes, unit=unit)
@@ -1008,7 +1028,7 @@ def set_dtype(self, dtype):
         return self
 
     def to_ndarray(self):
-        return ndarray([convert_if_categorical(val).to_ndarray() for val in self.values])
+        return ndarray([convert_if_categorical(val).to_ndarray() for val in self.levels])
 
     def to_list(self):
         return self.to_ndarray().tolist()
@@ -1057,7 +1077,7 @@ def register(self, user_defined_name):
             args={
                 "name": user_defined_name,
                 "objType": self.objType,
-                "num_idxs": len(self.values),
+                "num_idxs": len(self.levels),
                 "idx_names": [
                     json.dumps(
                         {
@@ -1070,9 +1090,9 @@ def register(self, user_defined_name):
                     )
                     if isinstance(v, Categorical)
                     else v.name
-                    for v in self.values
+                    for v in self.levels
                 ],
-                "idx_types": [v.objType for v in self.values],
+                "idx_types": [v.objType for v in self.levels],
             },
         )
         self.registered_name = user_defined_name
@@ -1131,7 +1151,7 @@ def lookup(self, key):
             raise TypeError("MultiIndex lookup failure")
         # if individual vals convert to pdarrays
         if not isinstance(key[0], pdarray):
-            dt = self.values[0].dtype if isinstance(self.values[0], pdarray) else akint64
+            dt = self.levels[0].dtype if isinstance(self.levels[0], pdarray) else akint64
             key = [akcast(array([x]), dt) for x in key]
 
         return in1d(self.index, key)
@@ -1200,7 +1220,7 @@ def to_hdf(
                     **({"segments": obj.segments.name} if obj.segments is not None else {}),
                 }
             )
-            for obj in self.values
+            for obj in self.levels
         ]
         return typecast(
             str,
@@ -1212,10 +1232,10 @@ def to_hdf(
                     "file_format": _file_type_to_int(file_type),
                     "write_mode": _mode_str_to_int(mode),
                     "objType": self.objType,
-                    "num_idx": len(self.values),
+                    "num_idx": len(self.levels),
                     "idx": index_data,
-                    "idx_objTypes": [obj.objType for obj in self.values],
-                    "idx_dtypes": [str(obj.dtype) for obj in self.values],
+                    "idx_objTypes": [obj.objType for obj in self.levels],
+                    "idx_dtypes": [str(obj.dtype) for obj in self.levels],
                 },
             ),
         )
@@ -1252,7 +1272,7 @@ def update_hdf(
         RuntimeError
             Raised if a server-side error is thrown saving the index
         TypeError
-            Raised if the Index values are a list.
+            Raised if the Index levels are a list.
 
         Notes
         ------
@@ -1271,8 +1291,8 @@ def update_hdf(
             _repack_hdf,
         )
 
-        if isinstance(self.values, list):
-            raise TypeError("Unable update hdf when Index values are a list.")
+        if isinstance(self.levels, list):
+            raise TypeError("Unable update hdf when Index levels are a list.")
 
         # determine the format (single/distribute) that the file was saved in
         file_type = _get_hdf_filetype(prefix_path + "*")
@@ -1289,7 +1309,7 @@ def update_hdf(
                     **({"segments": obj.segments.name} if obj.segments is not None else {}),
                 }
             )
-            for obj in self.values
+            for obj in self.levels
         ]
 
         generic_msg(
@@ -1300,10 +1320,10 @@ def update_hdf(
                 "file_format": _file_type_to_int(file_type),
                 "write_mode": _mode_str_to_int("append"),
                 "objType": self.objType,
-                "num_idx": len(self.values),
+                "num_idx": len(self.levels),
                 "idx": index_data,
-                "idx_objTypes": [obj.objType for obj in self.values],
-                "idx_dtypes": [str(obj.dtype) for obj in self.values],
+                "idx_objTypes": [obj.objType for obj in self.levels],
+                "idx_dtypes": [str(obj.dtype) for obj in self.levels],
                 "overwrite": True,
             },
         ),

arkouda/series.py

@@ -663,7 +663,7 @@ def topn(self, n: int = 10) -> Series:
 
     def _reindex(self, idx):
         if isinstance(self.index, MultiIndex):
-            new_index = MultiIndex(self.index[idx].values, name=self.index.name, names=self.index.names)
+            new_index = MultiIndex(self.index[idx].levels, name=self.index.name, names=self.index.names)
         elif isinstance(self.index, Index):
             new_index = Index(self.index[idx], name=self.index.name)
         else: