Creating high score leaderboards with Redis

gistfile1.txt

NOTE: You will need at least Redis 2.1.6 to use the ZREVRANGEBYSCORE method.

Add players to HIGHSCORES table:

	fossil:~ dczarnecki$ redis-cli 
	redis> zadd HIGHSCORES 1 player_1
	(integer) 1
	redis> zadd HIGHSCORES 2 player_2
	(integer) 1
	redis> zadd HIGHSCORES 3 player_3
	(integer) 1
	redis> zadd HIGHSCORES 4 player_4
	(integer) 1
	redis> zadd HIGHSCORES 4 player_5
	(integer) 1
	redis> zadd HIGHSCORES 6 player_6
	(integer) 1
	redis> zadd HIGHSCORES 7 player_7
	(integer) 1
	redis> zadd HIGHSCORES 8 player_8
	(integer) 1
	redis> zadd HIGHSCORES 9 player_9
	(integer) 1
	redis> zadd HIGHSCORES 10 player_10
	(integer) 1

Find out how many players are in the HIGHSCORES table:

	redis> zcard HIGHSCORES
	(integer) 10

Print out all the players that are in the HIGHSCORES table:

	redis> zrangebyscore HIGHSCORES -inf +inf WITHSCORES
	1. "player_1"
	2. "1"
	3. "player_2"
	4. "2"
	5. "player_3"
	6. "3"
	7. "player_4"
	8. "4"
	9. "player_5"
	10. "4"
	11. "player_6"
	12. "6"
	13. "player_7"
	14. "7"
	15. "player_8"
	16. "8"
	17. "player_9"
	18. "9"
	19. "player_10"
	20. "10"

Print out the 1st page of the HIGHSCORES table:

	redis> zrangebyscore HIGHSCORES -inf +inf WITHSCORES LIMIT 0 5
	 1) "player_1"
	 2) "1"
	 3) "player_2"
	 4) "2"
	 5) "player_3"
	 6) "3"
	 7) "player_4"
	 8) "4"
	 9) "player_5"
	10) "4"

Print out the 2nd page of the HIGHSCORES table:

	redis> zrangebyscore HIGHSCORES -inf +inf WITHSCORES LIMIT 5 -1
	 1) "player_6"
	 2) "6"
	 3) "player_7"
	 4) "7"
	 5) "player_8"
	 6) "8"
	 7) "player_9"
	 8) "9"
	 9) "player_10"
	10) "10"

Print out all the players that are in the HIGHSCORES table from highest score to lowest score:

	redis> zrevrangebyscore HIGHSCORES +inf -inf WITHSCORES
	 1) "player_10"
	 2) "10"
	 3) "player_9"
	 4) "9"
	 5) "player_8"
	 6) "8"
	 7) "player_7"
	 8) "7"
	 9) "player_6"
	10) "6"
	11) "player_5"
	12) "4"
	13) "player_4"
	14) "4"
	15) "player_3"
	16) "3"
	17) "player_2"
	18) "2"
	19) "player_1"
	20) "1"

Print out the 1st page of players that are in the HIGHSCORES table from highest score to lowest score:

	redis> zrevrangebyscore HIGHSCORES +inf -inf WITHSCORES LIMIT 0 5
	 1) "player_10"
	 2) "10"
	 3) "player_9"
	 4) "9"
	 5) "player_8"
	 6) "8"
	 7) "player_7"
	 8) "7"
	 9) "player_6"
	10) "6"

Print out the 2nd page of players that are in the HIGHSCORES table from highest score to lowest score:

	redis> zrevrangebyscore HIGHSCORES +inf -inf WITHSCORES LIMIT 5 -1
	 1) "player_5"
	 2) "4"
	 3) "player_4"
	 4) "4"
	 5) "player_3"
	 6) "3"
	 7) "player_2"
	 8) "2"
	 9) "player_1"
	10) "1"

Create an "Around Me" leaderboard with scores of individuals above and below me:

Find rank in reverse order:

	redis> zrevrank HIGHSCORES player_6
	(integer) 5

Get players above a given player:

	redis> zrevrangebyscore HIGHSCORES +inf -inf WITHSCORES LIMIT 2 3
	1) "player_9"
	2) "9"
	3) "player_8"
	4) "8"
	5) "player_7"
	6) "7"

Get players below a given player:

	redis> zrevrangebyscore HIGHSCORES +inf -inf WITHSCORES LIMIT 6 3
	1) "player_5"
	2) "4"
	3) "player_4"
	4) "4"
	5) "player_3"
	6) "3"

Another "Around Me" leaderboard:

	redis> zrevrank HIGHSCORES player_4
	(integer) 7

	redis> zrevrangebyscore HIGHSCORES +inf -inf WITHSCORES LIMIT 4 3
	1) "player_7"
	2) "7"
	3) "player_6"
	4) "6"
	5) "player_5"
	6) "4"

	redis> zrevrangebyscore HIGHSCORES +inf -inf WITHSCORES LIMIT 8 3
	1) "player_3"
	2) "3"
	3) "player_2"
	4) "2"
	5) "player_1"
	6) "1"

Actually, let's simplify the "Around Me" leaderboard to just be 2 calls and include the individual in the leaderboard results:

  redis> zrevrank HIGHSCORES player_6
  (integer) 4
  
  redis> zrevrangebyscore HIGHSCORES +inf -inf WITHSCORES LIMIT 1 7
  1. "player_9"
  2. "9"
  3. "player_8"
  4. "8"
  5. "player_7"
  6. "7"
  7. "player_6"
  8. "6"
  9. "player_5"
  10. "4"
  11. "player_4"
  12. "4"
  13. "player_3"
  14. "3"