diff --git a/tools/rostopic/src/rostopic/__init__.py b/tools/rostopic/src/rostopic/__init__.py
index 4b11424f3e..91760fbeaa 100644
--- a/tools/rostopic/src/rostopic/__init__.py
+++ b/tools/rostopic/src/rostopic/__init__.py
@@ -1119,42 +1119,58 @@ def _rostopic_list_bag(bag_file, topic=None):
                     break
 
 def _sub_rostopic_list(master, pubs, subs, publishers_only, subscribers_only, verbose, indent=''):
-    def topic_type(t, topic_types):
-        matches = [t_type for t_name, t_type in topic_types if t_name == t]
-        if matches:
-            return matches[0]
-        return 'unknown type'
-
     if verbose:
         topic_types = _master_get_topic_types(master)
 
         if not subscribers_only:
             print("\n%sPublished topics:"%indent)
-            for t, l in pubs:
-                if len(l) > 1:
-                    print(indent+" * %s [%s] %s publishers"%(t, topic_type(t, topic_types), len(l)))
+            for t, ttype, tlist in pubs:
+                if len(tlist) > 1:
+                    print(indent+" * %s [%s] %s publishers"%(t, ttype, len(tlist)))
                 else:
-                    print(indent+" * %s [%s] 1 publisher"%(t, topic_type(t, topic_types)))                    
+                    print(indent+" * %s [%s] 1 publisher"%(t, y))                    
 
         if not publishers_only:
             print(indent)
             print(indent+"Subscribed topics:")
-            for t,l in subs:
-                if len(l) > 1:
-                    print(indent+" * %s [%s] %s subscribers"%(t, topic_type(t, topic_types), len(l)))
+            for t, ttype, tlist in subs:
+                if len(tlist) > 1:
+                    print(indent+" * %s [%s] %s subscribers"%(t, ttype, len(llist)))
                 else:
-                    print(indent+" * %s [%s] 1 subscriber"%(t, topic_type(t, topic_types)))
+                    print(indent+" * %s [%s] 1 subscriber"%(t, y))
         print('')
     else:
         if publishers_only:
-            topics = [t for t,_ in pubs]
+            topics = [t for t,_,_ in pubs]
         elif subscribers_only:
-            topics = [t for t,_ in subs]
+            topics = [t for t,_,_ in subs]
         else:
-            topics = list(set([t for t,_ in pubs] + [t for t,_ in subs]))                
+            topics = list(set([t for t,_,_ in pubs] + [t for t,_,_ in subs]))                
         topics.sort()
         print('\n'.join(["%s%s"%(indent, t) for t in topics]))
 
+def get_topic_list(master=rosgraph.Master('/rostopic')):
+    def topic_type(t, topic_types):
+        matches = [t_type for t_name, t_type in topic_types if t_name == t]
+        if matches:
+            return matches[0]
+        return 'unknown type'
+
+    # Return an array of tuples; (<topic>, <type>, <node_count>)
+    state = master.getSystemState()
+    topic_types = _master_get_topic_types(master)
+    
+    pubs, subs, _ = state
+    pubs_out = []
+    for topic, nodes in pubs:
+        pubs_out.append((topic, topic_type(topic, topic_types), nodes))
+    subs_out = []
+    for topic, nodes in subs:
+        subs_out.append((topic, topic_type(topic, topic_types), nodes))
+
+    # List of published topics, list of subscribed topics.
+    return (pubs_out, subs_out)
+
 # #3145
 def _rostopic_list_group_by_host(master, pubs, subs):
     """
@@ -1163,7 +1179,7 @@ def _rostopic_list_group_by_host(master, pubs, subs):
     """
     def build_map(master, state, uricache):
         tmap = {}
-        for topic, tnodes in state:
+        for topic, ttype, tnodes in state:
             for p in tnodes:
                 if not p in uricache:
                    uricache[p] = master.lookupNode(p)
@@ -1202,15 +1218,11 @@ def _rostopic_list(topic, verbose=False,
     
     master = rosgraph.Master('/rostopic')
     try:
-        state = master.getSystemState()
-
-        pubs, subs, _ = state
+        pubs, subs = get_topic_list(master=master)
         if topic:
-            # filter based on topic
-            topic_ns = rosgraph.names.make_global_ns(topic)        
+            topic_ns = rosgraph.names.make_global_ns(topic)
             subs = (x for x in subs if x[0] == topic or x[0].startswith(topic_ns))
             pubs = (x for x in pubs if x[0] == topic or x[0].startswith(topic_ns))
-            
     except socket.error:
         raise ROSTopicIOException("Unable to communicate with master!")
 
@@ -1249,9 +1261,7 @@ def topic_type(t, topic_types):
 
     master = rosgraph.Master('/rostopic')
     try:
-        state = master.getSystemState()
-
-        pubs, subs, _ = state
+        pubs, subs = get_topic_list(master=master)
         # filter based on topic
         subs = [x for x in subs if x[0] == topic]
         pubs = [x for x in pubs if x[0] == topic]
diff --git a/tools/rostopic/test/test_rostopic.py b/tools/rostopic/test/test_rostopic.py
index 388bedd1f8..33da321cdf 100644
--- a/tools/rostopic/test/test_rostopic.py
+++ b/tools/rostopic/test/test_rostopic.py
@@ -281,7 +281,7 @@ def test_cmd_list(self):
         # test main entry
         rostopic.rostopicmain([cmd, 'list'])
 
-        # test directly
+        # test through running command
         topics = ['/chatter', '/foo/chatter', '/bar/chatter', '/rosout', '/rosout_agg'] 
 
         with fakestdout() as b:
@@ -289,6 +289,12 @@ def test_cmd_list(self):
             v = [x.strip() for x in b.getvalue().split('\n') if x.strip()]
             self.failIf(set(topics)-set(v))
 
+        # test through public function
+        topics = ['/chatter', '/foo/chatter', '/bar/chatter', '/rosout', '/rosout_agg'] 
+
+        v = rostopic.get_topic_list()
+        self.failIf(set(topics)-set(v))
+
         # publishers-only
         topics = ['/chatter', '/foo/chatter', '/bar/chatter', '/rosout', '/rosout_agg'] 
         with fakestdout() as b: