Implemented delete vector function based on the ID

nearpy/engine.py

@@ -96,6 +96,16 @@ def store_vector(self, v, data=None):
                 self.storage.store_vector(lshash.hash_name, bucket_key,
                                           nv, data)
 
+    def delete_vector(self, data):
+        """
+        Deletes vector v and his id (data) in all matching buckets in the storage.
+        The data argument must be JSON-serializable.
+        """
+
+        # Delete data id in each hashes
+        for lshash in self.lshashes:
+            self.storage.delete_vector(lshash.hash_name, data)
+
 
     def candidate_count(self, v):
         """

nearpy/storage/storage.py

@@ -30,6 +30,12 @@ def store_vector(self, hash_name, bucket_key, v, data):
         """
         raise NotImplementedError
 
+    def delete_vector(self, hash_name, data):
+        """
+        Deletes vector and JSON-serializable data in bucket with specified key.
+        """
+        raise NotImplementedError
+
     def get_bucket(self, hash_name, bucket_key):
         """
         Returns bucket content as list of tuples (vector, data).
@@ -59,6 +65,3 @@ def load_hash_configuration(self, hash_name):
         Loads and returns hash configuration
         """
         raise NotImplementedError
-
-
-

nearpy/storage/storage_memory.py

@@ -49,6 +49,14 @@ def store_vector(self, hash_name, bucket_key, v, data):
             self.buckets[hash_name][bucket_key] = []
         self.buckets[hash_name][bucket_key].append((v, data))
 
+    def delete_vector(self, hash_name, data):
+        """
+        Deletes vector and JSON-serializable data in bucket with specified key.
+        """
+        for bucket in self.buckets[hash_name].values():
+            bucket[:] = [(v, id_data) for v, id_data in bucket if id_data != data]
+
+
     def get_bucket(self, hash_name, bucket_key):
         """
         Returns bucket content as list of tuples (vector, data).
@@ -81,4 +89,3 @@ def load_hash_configuration(self, hash_name):
         Loads and returns hash configuration
         """
         return self.hash_configs.get(hash_name)
-

nearpy/tests/engine_tests.py

@@ -23,15 +23,18 @@
 import numpy
 import scipy
 import unittest
+import itertools
+
 
 from nearpy import Engine
 from nearpy.utils.utils import unitvec
-
+from nearpy.hashes import UniBucket
 
 class TestEngine(unittest.TestCase):
 
     def setUp(self):
         self.engine = Engine(1000)
+        numpy.random.seed(4)
 
     def test_storage_issue(self):
         engine1 = Engine(100)
@@ -73,5 +76,51 @@ def test_retrieval_sparse(self):
             self.assertEqual(y_data, x_data)
             self.assertAlmostEqual(y_distance, 0.0, delta=delta)
 
+    def get_keys(self, engine):
+        def get_bucket_keys(lshash):
+            bucket = engine.storage.buckets[lshash.hash_name][lshash.hash_name]
+            return (i for v, i in bucket)
+
+        return set(itertools.chain.from_iterable(
+            get_bucket_keys(lshash) for lshash in engine.lshashes))
+
+    def test_delete_vector_single_hash(self):
+        dim = 5
+        engine = Engine(dim, lshashes=[UniBucket('testHash')])
+        # Index 20 random vectors (set their data to a unique string)
+        for index in range(20):
+            v = numpy.random.randn(dim)
+            engine.store_vector(v, index)
+
+        keys = self.get_keys(engine)
+
+        engine.delete_vector(15)  #delete the vector with key = 15
+
+        new_keys = self.get_keys(engine)
+
+        self.assertGreater(len(keys), len(new_keys))  #new keys has 19 elements instead of 20
+        self.assertIn(15, keys)
+        self.assertNotIn(15, new_keys)  # the key 15 is the one missing
+
+    def test_delete_vector_multiple_hash(self):
+        dim = 5
+        hashes = [UniBucket('name_hash_%d' % k) for k in range(10)]
+        engine = Engine(dim, lshashes=hashes)
+        # Index 20 random vectors (set their data to a unique string)
+        for index in range(20):
+            v = numpy.random.randn(dim)
+            engine.store_vector(v, index)
+
+        keys = self.get_keys(engine)
+
+        engine.delete_vector(15)  #delete the vector with key = 15
+
+        new_keys = self.get_keys(engine)
+
+        self.assertGreater(len(keys), len(new_keys))  #new keys has 19 elements instead of 20
+        self.assertIn(15, keys)
+        self.assertNotIn(15, new_keys)  # the key 15 is the one missing
+
+
 if __name__ == '__main__':
     unittest.main()

nearpy/utils/utils.py

@@ -89,3 +89,4 @@ def want_string(arg, encoding='utf-8'):
     else:
         rv = arg
     return rv
+