Optimized by replacing filter() with dictionary lookup.

1 files changed, 13 insertions, 29 deletions

diff --git a/scripts/getrankings.py b/scripts/getrankings.py
index d23cb38..d8a0a5b 100644
--- a/scripts/getrankings.py
+++ b/scripts/getrankings.py
@@ -81,44 +81,28 @@ class GetRankings:
 
             if context2_prev_id >= 0:
                 # Compute deltas from previous ranking:
-                ranking_prev = execQuery(
+                ranking_prev_list = execQuery(
                     "SELECT benchmarkId, metricId, pos"
                     " FROM ranking"
                     " WHERE context2Id = %d"
                     " AND statId = %d;"
                     % (context2_prev_id, stat_id))
+                ranking_prev = {}
+                for benchmark_id, metric_id, pos in ranking_prev_list:
+                    ranking_prev[benchmark_id, metric_id] = pos
+
+                # Append deltas where applicable:
                 ranking_without_deltas = ranking
                 ranking = []
-                for row in ranking_without_deltas:
-                    benchmark_id = row[0]
-                    metric_id = row[1]
-                    context1_id = row[2]
-                    pos = row[3]
-                    value = row[4]
-
-                    new_row = [
-                        benchmark_id, metric_id, context1_id, pos, value]
-
+                for (benchmark_id, metric_id, context1_id, pos, value
+                     ) in ranking_without_deltas:
+                    row = [benchmark_id, metric_id, context1_id, pos, value]
                     if pos >= 0:
-
-                        # ### Maybe optimize the search for row_prev by storing
-                        # previous rankings in a dictionary with
-                        # (benchmark_id, metric_id) as key?
-                        row_prev = filter(
-                            lambda row: row[0] == benchmark_id
-                            and row[1] == metric_id,
-                            ranking_prev)
-
-                        assert len(row_prev) == 1
-                        assert len(row_prev[0]) == 3
-                        pos_prev = row_prev[0][2]
-
+                        pos_prev = ranking_prev[benchmark_id, metric_id]
                         if pos_prev >= 0:
                             delta = pos_prev - pos
-                            new_row.append(delta)
-
-
-                    ranking.append(new_row)
+                            row.append(delta)
+                    ranking.append(row)
 
 
 
@@ -184,7 +168,7 @@ class GetRankings:
                 'snapshots': map(
                     lambda s: (idToText("sha1", s[0]), s[1]), self.snapshots),
                 'rankings': self.rankings
-                }, sys.stdout, indent=4)
+                }, sys.stdout)
 
 
 class GetRankingsAsJSON(GetRankings):