How to use redis zset

Redis Ordered Sets (ZSets) are used to store ordered elements and sort by associated scores. The usage steps of ZSet include: 1. Create a ZSet; 2. Add a member; 3. Get a member score; 4. Get a ranking; 5. Get a member in the ranking range; 6. Delete a member; 7. Get the number of elements; 8. Get the number of members in the score range.

Redis Ordered Set (ZSet) Usage

Redis Ordered Sets (ZSet) is a special data structure that stores elements as an ordered set and sorts them according to the scores associated with each element. ZSet is ideal for operations that require sorting elements and finding them quickly.

Steps to use ZSet:

1. Create a ZSet:

 <code>ZADD key score member [score member ...]</code>

• key: The name of ZSet
• score: The score associated with the member
• member: Member to add

2. Add members:
Use the ZADD command to add new members or update scores for existing members:

 <code>ZADD key score member</code>

3. Obtain member scores:

 <code>ZSCORE key member</code>

• Returns the score of the specified member, and if the member does not exist, returns nil.

4. Get rankings:

 <code>ZRANK key member</code>

• Returns the ranking of members in ZSet (starting from 0).

5. Obtain the ranking range of members:

 <code>ZRANGE key start stop [WITHSCORES]</code>

• Returns a list of members within the specified ranking range, and chooses whether to include scores.

6. Delete members:

 <code>ZREM key member [member ...]</code>

• Delete the specified member.

7. Get the number of elements of ZSet:

 <code>ZCARD key</code>

8. Get the number of members within the score range of ZSet:

 <code>ZCOUNT key min max</code>

Example:

 <code>ZADD my_zset 100 "Member A" ZADD my_zset 200 "Member B" ZADD my_zset 300 "Member C" ZSCORE my_zset "Member A" # 返回100 ZRANK my_zset "Member B" # 返回1 ZRANGE my_zset 0 1 # 返回["Member A", "Member B"]</code>

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