adding inverse and counts functions written via numpy

tests/unique_counts.py

@@ -0,0 +1,13 @@
+def unique_counts(arr):
+    if not isinstance(arr, ragged.array):
+        print("Input is not a ragged array")
+
+    if len(arr)==1:
+        return [(arr[0], 1)]
+
+    arr_flat=ak.ravel(arr)
+    arr_np = ak.to_numpy(arr_flat)
+    unique_elements, counts = np.unique(arr_np, return_counts=True)
+    unique_arr_counts = list(zip(unique_elements, counts))
+
+    return unique_arr_counts

tests/unique_inverse.py

@@ -0,0 +1,19 @@
+def unique_inverse(arr):
+    if not isinstance(arr, ragged.array):
+        print("Input is not a ragged array")
+
+    if len(arr) == 1:
+        return arr, np.array([0])
+
+    arr_list=ak.ravel(arr)
+    arr_np = ak.to_numpy(arr_list)
+    unique_elements, first_indices = np.unique(arr_np, return_index=True)
+
+    sorted_indices = np.argsort(first_indices)
+    unique_elements = unique_elements[sorted_indices]
+    first_indices = first_indices[sorted_indices]
+
+    unique_arr = ak.from_numpy(unique_elements)
+    unique_indices_arr = ak.from_numpy(first_indices)
+
+    return unique_arr, unique_indices_arr