Added attach, register, and unregister functionality. Removed groupin…

…g from these features because groupby does not yet support them. Added testing to validate functionality.

arkouda/segarray.py

@@ -1,6 +1,6 @@
 from __future__ import annotations
 
-from arkouda.pdarrayclass import pdarray, is_sorted
+from arkouda.pdarrayclass import pdarray, is_sorted, attach_pdarray
 from arkouda.numeric import cumsum
 from arkouda.dtypes import isSupportedInt
 from arkouda.dtypes import int64 as akint64
@@ -1015,5 +1015,26 @@ def setxor(self, other):
             segments[truth] = segments[arange(self.size)[truth] + 1]
             return SegArray(segments, new_values[g.permutation])
 
-# Register/Attach functionality has been removed until it is added for GroupBy.
-# Please refer to ticket #1122 (https://github.com/Bears-R-Us/arkouda/issues/1122 for updates
+    def register(self, name, segment_suffix='_segments', value_suffix='_values', length_suffix='_lengths', grouping_suffix='_grouping'):
+        if len(set((segment_suffix, value_suffix, length_suffix, grouping_suffix))) != 4:
+            raise ValueError("Suffixes must all be different")
+        self.segments.register(name+segment_suffix)
+        self.values.register(name+value_suffix)
+        self.lengths.register(name+length_suffix)
+        # TODO - groupby does not have register.
+        # self.grouping.register(name+grouping_suffix)
+
+    def unregister(self):
+        self.segments.unregister()
+        self.values.unregister()
+        self.lengths.unregister()
+        # TODO - groupby does not have unregister.
+        #self.grouping.unregister()
+
+    @classmethod
+    def attach(cls, name, segment_suffix='_segments', value_suffix='_values', length_suffix='_lengths', grouping_suffix='_grouping'):
+        if len(set((segment_suffix, value_suffix, length_suffix, grouping_suffix))) != 4:
+            raise ValueError("Suffixes must all be different")
+        # TODO - add grouping attaching grouping=ak.GroupBy.attach(name+grouping_suffix)
+        return cls(attach_pdarray(name+segment_suffix), attach_pdarray(name+value_suffix),
+                   lengths=attach_pdarray(name+length_suffix))

tests/segarray_test.py

@@ -571,4 +571,22 @@ def test_setxor(self):
         xor = segarr.setxor(segarr_2)
         self.assertListEqual(xor.lengths.to_ndarray().tolist(), [0, 2])
         self.assertListEqual(xor[0].tolist(), [])
-        self.assertListEqual(xor[1].tolist(), [3, 4])
+        self.assertListEqual(xor[1].tolist(), [3, 4])
+
+    def test_register_attach(self):
+        a = [1, 2, 3]
+        b = [6, 7, 8]
+
+        segarr = ak.SegArray(ak.array([0, len(a)]), ak.array(a + b))
+        #register the seg array
+        segarr.register('segarrtest')
+
+        segarr_2 = ak.SegArray.attach('segarrtest')
+
+        self.assertEqual(segarr.size, segarr_2.size)
+        self.assertListEqual(segarr.lengths.to_ndarray().tolist(), segarr_2.lengths.to_ndarray().tolist())
+        self.assertListEqual(segarr.segments.to_ndarray().tolist(), segarr_2.segments.to_ndarray().tolist())
+        self.assertListEqual(segarr.values.to_ndarray().tolist(), segarr_2.values.to_ndarray().tolist())
+
+        segarr.unregister()
+        self.assertEqual(len(ak.list_registry()), 0)