seantalts

feed_insights=# explain  select count(distinct(user_id)) from interests where keywords in (select keywords from interests group by keywords having count(*) > 30);
                                            QUERY PLAN                                             
---------------------------------------------------------------------------------------------------
Aggregate  (cost=2232807.48..2232807.49 rows=1 width=4)
   ->  Hash Join  (cost=1780566.44..2221413.32 rows=4557663 width=4)
         Hash Cond: (public.interests.keywords = public.interests.keywords)
         ->  Seq Scan on interests  (cost=0.00..172441.36 rows=9188836 width=19)
         ->  Hash  (cost=1778239.13..1778239.13 rows=133865 width=15)
               ->  GroupAggregate  (cost=1706310.89..1776900.48 rows=133865 width=15)
                     Filter: (count(*) > 30)

seantalts

import time

input = ['a', 'b', 'c', 'd', 'e', 'f']
iterations = 1000000

start = time.time()
for i in xrange(iterations):
    s = dict([(x.lower(), i) for i, x in enumerate(input)])
end = time.time()
print "First thing took %s seconds" % (end - start)