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Today, the editor will bring you an article about Redis ranking system. The editor thinks it is very practical, so I will share it for you as a reference. Let's follow the editor and have a look.

There is a very special data type in redis-ordered collections. The concept of a set that we have learned before is that all the elements in the set are unique and disordered. But how did there be an orderly set here, and how did he achieve it?

The elements in the ordered set are still unique, but each element is given a socre (score), through which the ordering is achieved. As shown in the following figure:

Ordered set API

Here are a few ordered collections of API. To achieve the ranking function, you need to know the use of these API.

ZAdd

We want to set up an ordered list of player 2k ability values, using player names as elements and ability values as scores.

Curry's projection ability is 100, James 92, Harden 96, Paul 97

Sadd can add one or more elements at a time

127.0.0.1 zadd 2kplayer:shoot 6379 [1] > integer 100 curry (integer) 1127.0.1 integer > zadd 2kplayer:shoot 92 james 96 harden 97 paul (integer) 3

ZIncrBy

Over the past month, Harden burst seed in succession and scored high scores crazily, so 2k decided to increase his projection ability by 2 points.

127.0.0.1 zincrby 2kplayer:shoot 6379 [1] > 2 harden "98"

ZRange 、 zRevRange

Now we want to know which three players are in the top three.

127.0.1 james 6379 [1] > zrange 2kplayer:shoot 0 2 withscores1) "james" 2) "92" 3) "paul" 4) "97" 5) "harden" 6) "98"

Redis uses positive order by default, and the scores are sorted from small to large. So we need to use zRevRange

127.0.1 zrevrange 2kplayer:shoot 6379 [1] > curry 0 2 withscores1) "curry" 2) "100" 3) "harden" 4) "98" 5) "paul" 6) "97"

ZUnionStore

2k ability value has many aspects, projection is only one of them, speed, layup and so on are all part of the ability value.

127.0.1 paul 6379 [1] > zadd 2kplayer:speed 99 james 90 paul 90 curry 93 harden (integer) 4

At this time, if you want to know the player's comprehensive ability, you need to add up the scores of each item.

127.0.0.1 zunionstore 2kplayer 2kplayer:shoot 2kplayer:speed (integer) 4127.0.1 zrange 2kplayer 0-1 withscores1) "paul" 2) "187" 3) "curry" 4) "190" 5) "harden" 6) "191" 7) "james" 8) "191"

Realize the ranking system

The scene is as follows: a video-on-demand system, which is watched by many people every day. The system has a list function to show the most watched videos. It is divided into today's list, three-day list, weekly ranking and monthly list.

Idea: first, count the number of video views on a daily basis, and then work out today's list, three-day list, and so on.

The pseudo code for counting the number of video views is as follows:

/ / watch video function view ($videoId) {$key = 'video:view:'.date (' Ymurmmurd`); if (! $redis- > exists ($key)) {$redis- > zIncrBy ($key, 1, $videoId); $redis- > expire ($key, 86400 * 30);} $redis- > zIncrBy ($key, 1, $videoId);}

It is the hottest today

One of the hottest things to note today is that when a new day begins, the data may be empty or small. So we can combine today's and yesterday's data, but reset today's data a little higher.

The pseudo code for today's hottest feature implementation is as follows:

Function todayHot () {$tokeyKey = 'video:view:'.date (' Yamazd`); $yesKey = 'video:view:'. Date ('Yellowmkids, time ()-86400); $keyUnion = "view:rank:today"; $redis- > zUnionStore ($keyUnion, [$tokeyKey, $yesKey], [10,1]); / / take the top 100 return $redis- > zRevRange ($keyUnion, 0,99);}

Three-day list

Function threeHot () {$keyUnion = 'view:rank:three'; $unionKeys = []; for ($iTun0; $I

ZUnionStore ($keyUnion, $unionKeys); return $redis- > zRevRange ($keyUnion, 0,99, true);}

The weekly list, monthly list, etc., are the same as the three-day list, so the code will not be posted.

On the production of Redis ranking system to share here, I hope the above content can be of some help to you, can learn more knowledge. If you like this article, you might as well share it for more people to see.

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