LLEN

语法

LLEN key

可用版本: Redis 开源版 1.0.0
时间复杂度: O(1)
ACL 分类: @read, @list, @fast,

返回存储在 key 处的列表的长度。如果 key 不存在，则将其解释为空列表并返回 0。如果存储在 key 处的值不是列表，则返回错误。

示例

>_ Redis CLI

redis> LPUSH mylist "World"
(integer) 1
redis> LPUSH mylist "Hello"
(integer) 2
redis> LLEN mylist
(integer) 2

Python

import redis

r = redis.Redis(decode_responses=True)

res1 = r.lpush("mylist", "world")
print(res1) # >>> 1

res2 = r.lpush("mylist", "hello")
print(res2) # >>> 2

res3 = r.lrange("mylist", 0, -1)
print(res3)  # >>> [ "hello", "world" ]


res4 = r.rpush("mylist", "one");
print(res4) # >>> 1

res5 = r.rpush("mylist", "two")
print(res5) # >>> 2

res6 = r.rpush("mylist", "three")
print(res6) # >>> 3

res7 = r.lrange('mylist', 0, 0)
print(res7) # >>> [ 'one' ]

res8 = r.lrange('mylist', -3, 2)
print(res8) # >>> [ 'one', 'two', 'three' ]

res9 = r.lrange('mylist', -100, 100)
print(res9) # >>> [ 'one', 'two', 'three' ]

res10 = r.lrange('mylist', 5, 10)
print(res10) # >>> []


res11 = r.lpush("mylist", "World")
print(res11) # >>> 1

res12 = r.lpush("mylist", "Hello")
print(res12) # >>> 2

res13 = r.llen("mylist")
print(res13)  # >>> 2


res14 = r.rpush("mylist", "hello")
print(res14) # >>> 1

res15 = r.rpush("mylist", "world")
print(res15) # >>> 2

res16 = r.lrange("mylist", 0, -1)
print(res16)  # >>> [ "hello", "world" ]


res17 = r.rpush("mylist", *["one", "two", "three", "four", "five"])
print(res17) # >>> 5

res18 = r.lpop("mylist")
print(res18) # >>> "one"

res19 = r.lpop("mylist", 2)
print(res19) # >>> ['two', 'three']

res17 = r.lrange("mylist", 0, -1)
print(res17)  # >>> [ "four", "five" ]


res18 = r.rpush("mylist", *["one", "two", "three", "four", "five"])
print(res18) # >>> 5

res19 = r.rpop("mylist")
print(res19) # >>> "five"

res20 = r.rpop("mylist", 2)
print(res20) # >>> ['four', 'three']

res21 = r.lrange("mylist", 0, -1)
print(res21)  # >>> [ "one", "two" ]

Node.js

import assert from 'node:assert';
import { createClient } from 'redis';

const client = createClient();
await client.connect().catch(console.error);

const res1 = await client.lPush('mylist', 'world');
console.log(res1); // 1

const res2 = await client.lPush('mylist', 'hello');
console.log(res2); // 2

const res3 = await client.lRange('mylist', 0, -1);
console.log(res3); // [ 'hello', 'world' ]


const res4 = await client.rPush('mylist', 'one');
console.log(res4); // 1

const res5 = await client.rPush('mylist', 'two');
console.log(res5); // 2

const res6 = await client.rPush('mylist', 'three');
console.log(res6); // 3

const res7 = await client.lRange('mylist', 0, 0);
console.log(res7); // [ 'one' ]

const res8 = await client.lRange('mylist', -3, 2);
console.log(res8); // [ 'one', 'two', 'three' ]

const res9 = await client.lRange('mylist', -100, 100);
console.log(res9); // [ 'one', 'two', 'three' ]

const res10 = await client.lRange('mylist', 5, 10);
console.log(res10); // []


const res11 = await client.lPush('mylist', 'World');
console.log(res11); // 1

const res12 = await client.lPush('mylist', 'Hello');
console.log(res12); // 2

const res13 = await client.lLen('mylist');
console.log(res13); // 2


const res14 = await client.rPush('mylist', 'hello');
console.log(res14); // 1

const res15 = await client.rPush('mylist', 'world');
console.log(res15); // 2

const res16 = await client.lRange('mylist', 0, -1);
console.log(res16); // [ 'hello', 'world' ]


const res17 = await client.rPush('mylist', ["one", "two", "three", "four", "five"]);
console.log(res17); // 5

const res18 = await client.lPop('mylist');
console.log(res18); // 'one'

const res19 = await client.lPopCount('mylist', 2);
console.log(res19); // [ 'two', 'three' ]

const res20 = await client.lRange('mylist', 0, -1);
console.log(res20); // [ 'four', 'five' ]


const res21 = await client.rPush('mylist', ["one", "two", "three", "four", "five"]);
console.log(res21); // 5

const res22 = await client.rPop('mylist');
console.log(res22); // 'five'

const res23 = await client.rPopCount('mylist', 2);
console.log(res23); // [ 'four', 'three' ]

const res24 = await client.lRange('mylist', 0, -1);
console.log(res24); // [ 'one', 'two' ]


await client.quit();

Java-Sync

import java.util.List;

import redis.clients.jedis.UnifiedJedis;

import static org.junit.jupiter.api.Assertions.assertEquals;

public class CmdsListExample {

    public void run() {
        UnifiedJedis jedis = new UnifiedJedis("redis://localhost:6379");

        long lLenResult1 = jedis.lpush("mylist", "World");
        System.out.println(lLenResult1); // >>> 1

        long lLenResult2 = jedis.lpush("mylist", "Hello");
        System.out.println(lLenResult2); // >>> 2

        long lLenResult3 = jedis.llen("mylist");
        System.out.println(lLenResult3); // >>> 2

        long lPopResult1 = jedis.rpush(
            "mylist", "one", "two", "three", "four", "five"
        );
        System.out.println(lPopResult1); // >>> 5

        String lPopResult2 = jedis.lpop("mylist");
        System.out.println(lPopResult2); // >>> one

        List<String> lPopResult3 = jedis.lpop("mylist", 2);
        System.out.println(lPopResult3); // >>> [two, three]

        List<String> lPopResult4 = jedis.lrange("mylist", 0, -1);
        System.out.println(lPopResult4); // >>> [four, five]

        long lPushResult1 = jedis.lpush("mylist", "World");
        System.out.println(lPushResult1); // >>> 1

        long lPushResult2 = jedis.lpush("mylist", "Hello");
        System.out.println(lPushResult2); // >>> 2

        List<String> lPushResult3 = jedis.lrange("mylist", 0, -1);
        System.out.println(lPushResult3);
        // >>> [Hello, World]

        long lRangeResult1 = jedis.rpush("mylist", "one", "two", "three");
        System.out.println(lRangeResult1); // >>> 3

        List<String> lRangeResult2 = jedis.lrange("mylist", 0, 0);
        System.out.println(lRangeResult2); // >>> [one]

        List<String> lRangeResult3 = jedis.lrange("mylist", -3, 2);
        System.out.println(lRangeResult3); // >>> [one, two, three]

        List<String> lRangeResult4 = jedis.lrange("mylist", -100, 100);
        System.out.println(lRangeResult4); // >>> [one, two, three]

        List<String> lRangeResult5 = jedis.lrange("mylist", 5, 10);
        System.out.println(lRangeResult5); // >>> []

        long rPopResult1 = jedis.rpush(
            "mylist", "one", "two", "three", "four", "five"
        );
        System.out.println(rPopResult1); // >>> 5

        String rPopResult2 = jedis.rpop("mylist");
        System.out.println(rPopResult2); // >>> five

        List<String> rPopResult3 = jedis.rpop("mylist", 2);
        System.out.println(rPopResult3); // >>> [four, three]

        List<String> rPopResult4 = jedis.lrange("mylist", 0, -1);
        System.out.println(rPopResult4); // >>> [one, two]

        long rPushResult1 = jedis.rpush("mylist", "hello");
        System.out.println(rPushResult1); // >>> 1

        long rPushResult2 = jedis.rpush("mylist", "world");
        System.out.println(rPushResult2); // >>> 2

        List<String> rPushResult3 = jedis.lrange("mylist", 0, -1);
        System.out.println(rPushResult3); // >>> [hello, world]

        jedis.close();
    }
}

package example_commands_test

import (
	"context"
	"fmt"

	"github.com/redis/go-redis/v9"
)


func ExampleClient_cmd_llen() {
	ctx := context.Background()

	rdb := redis.NewClient(&redis.Options{
		Addr:     "localhost:6379",
		Password: "", // no password docs
		DB:       0,  // use default DB
	})


	lPushResult1, err := rdb.LPush(ctx, "mylist", "World").Result()

	if err != nil {
		panic(err)
	}

	fmt.Println(lPushResult1) // >>> 1

	lPushResult2, err := rdb.LPush(ctx, "mylist", "Hello").Result()

	if err != nil {
		panic(err)
	}

	fmt.Println(lPushResult2) // >>> 2

	lLenResult, err := rdb.LLen(ctx, "mylist").Result()

	if err != nil {
		panic(err)
	}

	fmt.Println(lLenResult) // >>> 2

}
func ExampleClient_cmd_lpop() {
	ctx := context.Background()

	rdb := redis.NewClient(&redis.Options{
		Addr:     "localhost:6379",
		Password: "", // no password docs
		DB:       0,  // use default DB
	})


	RPushResult, err := rdb.RPush(ctx,
		"mylist", "one", "two", "three", "four", "five",
	).Result()

	if err != nil {
		panic(err)
	}

	fmt.Println(RPushResult) // >>> 5

	lPopResult, err := rdb.LPop(ctx, "mylist").Result()

	if err != nil {
		panic(err)
	}

	fmt.Println(lPopResult) // >>> one

	lPopCountResult, err := rdb.LPopCount(ctx, "mylist", 2).Result()

	if err != nil {
		panic(err)
	}

	fmt.Println(lPopCountResult) // >>> [two three]

	lRangeResult, err := rdb.LRange(ctx, "mylist", 0, -1).Result()

	if err != nil {
		panic(err)
	}

	fmt.Println(lRangeResult) // >>> [four five]

}

func ExampleClient_cmd_lpush() {
	ctx := context.Background()

	rdb := redis.NewClient(&redis.Options{
		Addr:     "localhost:6379",
		Password: "", // no password docs
		DB:       0,  // use default DB
	})


	lPushResult1, err := rdb.LPush(ctx, "mylist", "World").Result()

	if err != nil {
		panic(err)
	}

	fmt.Println(lPushResult1) // >>> 1

	lPushResult2, err := rdb.LPush(ctx, "mylist", "Hello").Result()

	if err != nil {
		panic(err)
	}

	fmt.Println(lPushResult2) // >>> 2

	lRangeResult, err := rdb.LRange(ctx, "mylist", 0, -1).Result()

	if err != nil {
		panic(err)
	}

	fmt.Println(lRangeResult) // >>> [Hello World]

}

func ExampleClient_cmd_lrange() {
	ctx := context.Background()

	rdb := redis.NewClient(&redis.Options{
		Addr:     "localhost:6379",
		Password: "", // no password docs
		DB:       0,  // use default DB
	})


	RPushResult, err := rdb.RPush(ctx, "mylist",
		"one", "two", "three",
	).Result()

	if err != nil {
		panic(err)
	}

	fmt.Println(RPushResult) // >>> 3

	lRangeResult1, err := rdb.LRange(ctx, "mylist", 0, 0).Result()

	if err != nil {
		panic(err)
	}

	fmt.Println(lRangeResult1) // >>> [one]

	lRangeResult2, err := rdb.LRange(ctx, "mylist", -3, 2).Result()

	if err != nil {
		panic(err)
	}

	fmt.Println(lRangeResult2) // >>> [one two three]

	lRangeResult3, err := rdb.LRange(ctx, "mylist", -100, 100).Result()

	if err != nil {
		panic(err)
	}

	fmt.Println(lRangeResult3) // >>> [one two three]

	lRangeResult4, err := rdb.LRange(ctx, "mylist", 5, 10).Result()

	if err != nil {
		panic(err)
	}

	fmt.Println(lRangeResult4) // >>> []

}

func ExampleClient_cmd_rpop() {
	ctx := context.Background()

	rdb := redis.NewClient(&redis.Options{
		Addr:     "localhost:6379",
		Password: "", // no password docs
		DB:       0,  // use default DB
	})


	rPushResult, err := rdb.RPush(ctx, "mylist",
		"one", "two", "three", "four", "five",
	).Result()

	if err != nil {
		panic(err)
	}

	fmt.Println(rPushResult) // >>> 5

	rPopResult, err := rdb.RPop(ctx, "mylist").Result()

	if err != nil {
		panic(err)
	}

	fmt.Println(rPopResult) // >>> five

	rPopCountResult, err := rdb.RPopCount(ctx, "mylist", 2).Result()

	if err != nil {
		panic(err)
	}

	fmt.Println(rPopCountResult) // >>> [four three]

	lRangeResult, err := rdb.LRange(ctx, "mylist", 0, -1).Result()

	if err != nil {
		panic(err)
	}

	fmt.Println(lRangeResult) // >>> [one two]

}

func ExampleClient_cmd_rpush() {
	ctx := context.Background()

	rdb := redis.NewClient(&redis.Options{
		Addr:     "localhost:6379",
		Password: "", // no password docs
		DB:       0,  // use default DB
	})


	rPushResult1, err := rdb.RPush(ctx, "mylist", "Hello").Result()

	if err != nil {
		panic(err)
	}

	fmt.Println(rPushResult1) // >>> 1

	rPushResult2, err := rdb.RPush(ctx, "mylist", "World").Result()

	if err != nil {
		panic(err)
	}

	fmt.Println(rPushResult2) // >>> 2

	lRangeResult, err := rdb.LRange(ctx, "mylist", 0, -1).Result()

	if err != nil {
		panic(err)
	}

	fmt.Println(lRangeResult) // >>> [Hello World]

}

在交互式控制台中尝试这些命令

RESP2/RESP3 回复

整数回复: 列表的长度。

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