replace some filter/map calls with list comps

These are places where the surrounding/calling code needs a list, not an iter.

beets/autotag/hooks.py

@@ -547,7 +547,7 @@ def albums_for_id(album_id):
     for a in plugin_albums:
         plugins.send(u'albuminfo_received', info=a)
     candidates.extend(plugin_albums)
-    return filter(None, candidates)
+    return [a for a in candidates if a]
 
 
 def tracks_for_id(track_id):
@@ -557,7 +557,7 @@ def tracks_for_id(track_id):
     for t in plugin_tracks:
         plugins.send(u'trackinfo_received', info=t)
     candidates.extend(plugin_tracks)
-    return filter(None, candidates)
+    return [t for t in candidates if t]
 
 
 def album_candidates(items, artist, album, va_likely):

beetsplug/missing.py

@@ -133,7 +133,7 @@ class MissingPlugin(BeetsPlugin):
     def _missing(self, album):
         """Query MusicBrainz to determine items missing from `album`.
         """
-        item_mbids = map(lambda x: x.mb_trackid, album.items())
+        item_mbids = [x.mb_trackid for x in album.items()]
         if len([i for i in album.items()]) < album.albumtotal:
             # fetch missing items
             # TODO: Implement caching that without breaking other stuff

beetsplug/spotify.py

@@ -124,9 +124,8 @@ class SpotifyPlugin(BeetsPlugin):
             # Apply market filter if requested
             region_filter = self.config['region_filter'].get()
             if region_filter:
-                r_data = filter(
-                    lambda x: region_filter in x['available_markets'], r_data
-                )
+                r_data = [x for x in r_data if region_filter
+                          in x['available_markets']]
 
             # Simplest, take the first result
             chosen_result = None
@@ -163,7 +162,7 @@ class SpotifyPlugin(BeetsPlugin):
 
     def output_results(self, results):
         if results:
-            ids = map(lambda x: x['id'], results)
+            ids = [x['id'] for x in results]
             if self.config['mode'].get() == "open":
                 self._log.info(u'Attempting to open Spotify with playlist')
                 spotify_url = self.playlist_partial + ",".join(ids)

test/test_query.py

@@ -37,11 +37,11 @@ from beets import util
 class TestHelper(helper.TestHelper):
 
     def assertInResult(self, item, results):  # noqa
-        result_ids = map(lambda i: i.id, results)
+        result_ids = [i.id for i in results]
         self.assertIn(item.id, result_ids)
 
     def assertNotInResult(self, item, results):  # noqa
-        result_ids = map(lambda i: i.id, results)
+        result_ids = [i.id for i in results]
         self.assertNotIn(item.id, result_ids)