How to get data in redis

The methods to obtain Redis data are: General methods: 1. Use the GET command to obtain a single key value; 2. Use the MGET command to obtain multiple key values. Language-specific methods: Depending on the language and client library used, specialized methods for getting data are available, such as Python's redis.Redis().get(), Node.js's client.get(), and Java's jedis.get() . In addition, you can also use the TYPE command to get the type of the key, and the EXISTS command to check whether the key exists.

How to get data from Redis

Redis is a popular key-value storage database mainly used for storage and get data. There are several ways to get data in Redis, depending on the language and client used.

General method

1. GET command

The GET command is a general method for obtaining key values. The syntax is as follows:

<code>GET key</code>

where key is the key from which the value is to be obtained.

2. MGET command

The MGET command is used to obtain the values ​​of multiple keys at one time. The syntax is as follows:

<code>MGET key1 key2 ... keyn</code>

where key1, key2, ..., keyn is the key to get the value from.

Language-specific clients

For different programming languages, there are usually specialized Redis client libraries that provide a more convenient way to obtain data. Here are examples from common languages:

Python

<code class="python">import redis

r = redis.Redis()
value = r.get('key')</code>

Node.js

<code class="javascript">const redis = require('redis');

const client = redis.createClient();
client.get('key', (err, value) => {
  // 处理结果
});</code>

Java

<code class="java">import redis.clients.jedis.Jedis;

Jedis jedis = new Jedis();
String value = jedis.get("key");</code>

Get the data type

In addition to getting the key value, you can also get the value type. You can use the following commands:

1. TYPE command

The TYPE command returns the type of key. The syntax is as follows:

<code>TYPE key</code>

Possible types include:

• string
• list
• set
• zset
• hash

2. EXISTS command

The EXISTS command checks whether the key exists. The syntax is as follows:

<code>EXISTS key</code>

If the key exists, return 1, otherwise return 0.

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