Redis Sorted Set: Remove by Score (Detailed Guide w/ Code Examples)

Use Case(s)

Removing elements from a Redis Sorted Set based on their scores is useful when managing time-sensitive data, such as expiring cache entries, removing outdated records, or trimming leaderboards.

Code Examples

Python

import redis

client = redis.StrictRedis(host='localhost', port=6379, db=0)

# Add some elements with scores
client.zadd('myset', {'member1': 10, 'member2': 20, 'member3': 30})

# Remove all elements with scores between 15 and 25 (inclusive)
client.zremrangebyscore('myset', 15, 25)

Node.js

const redis = require('redis');
const client = redis.createClient();

client.zadd('myset', 10, 'member1');
client.zadd('myset', 20, 'member2');
client.zadd('myset', 30, 'member3');

client.zremrangebyscore('myset', 15, 25, (err, response) => {
    if (err) throw err;
    console.log(response); // Number of members removed
});

Golang

package main

import (
	"fmt"
	"github.com/go-redis/redis/v8"
	"context"
)

func main() {
	ctx := context.Background()
	client := redis.NewClient(&redis.Options{
		Addr: "localhost:6379",
	})

	client.ZAdd(ctx, "myset", &redis.Z{Score: 10, Member: "member1"})
	client.ZAdd(ctx, "myset", &redis.Z{Score: 20, Member: "member2"})
	client.ZAdd(ctx, "myset", &redis.Z{Score: 30, Member: "member3"})

	client.ZRemRangeByScore(ctx, "myset", "15", "25")
}

Best Practices

• Always handle possible errors when working with Redis operations.
• Make use of transactions (MULTI/EXEC) if multiple operations depend on each other to maintain atomicity.

Common Mistakes

• Not converting score ranges to string when required in certain languages or libraries (e.g., Go).
• Forgetting to check the number of removed elements to ensure the operation's success.

FAQs

Q: What happens if there are no elements within the specified score range? A: The command will simply return 0, indicating no elements were removed.

Q: Can score ranges be inclusive/exclusive? A: Yes, you can specify inclusive ranges using [min,max] and exclusive ranges using (min,max).