distinct helper - Collection.distinct

Mike Dirolf · Mike Dirolf · commit 84d8d2f1c6f3 · 2009-10-27T12:46:22.000-04:00
diff --git a/pymongo/collection.py b/pymongo/collection.py
@@ -686,6 +686,19 @@ def rename(self, new_name):
 
         self.__database.connection().admin._command(rename_command)
 
+    def distinct(self, key):
+        """Get a list of distinct values for `key` among all documents in this
+        collection.
+
+        :Parameters:
+          - `key`: name of key for which we want to get the distinct values
+        """
+        if not isinstance(key, types.StringTypes):
+            raise TypeError("key must be an instance of (str, unicode)")
+
+        command = SON([("distinct", self.__collection_name), ("key", key)])
+        return self.__database._command(command)["values"]
+
     def __iter__(self):
         return self
 
diff --git a/test/test_collection.py b/test/test_collection.py
@@ -791,6 +791,32 @@ def test_cursor_timeout(self):
         list(self.db.test.find(timeout=False))
         list(self.db.test.find(timeout=True))
 
+    def test_distinct(self):
+        self.db.drop_collection("test")
+
+        self.db.test.save({"a": 1})
+        self.db.test.save({"a": 2})
+        self.db.test.save({"a": 2})
+        self.db.test.save({"a": 2})
+        self.db.test.save({"a": 3})
+
+        distinct = self.db.test.distinct("a")
+        distinct.sort()
+
+        self.assertEqual([1, 2, 3], distinct)
+
+        self.db.drop_collection("test")
+
+        self.db.test.save({"a": {"b": "a"}, "c": 12})
+        self.db.test.save({"a": {"b": "b"}, "c": 12})
+        self.db.test.save({"a": {"b": "c"}, "c": 12})
+        self.db.test.save({"a": {"b": "c"}, "c": 12})
+
+        distinct = self.db.test.distinct("a.b")
+        distinct.sort()
+
+        self.assertEqual(["a", "b", "c"], distinct)
+
 
 if __name__ == "__main__":
     unittest.main()
