Redis Command: GETRANGE

Summary

Command Name	GETRANGE
Usage	Get a substring by range
Group	string
ACL Category	@read @string @slow
Time Complexity	O(N) **N is the length of the returned string
Flag	READONLY
Arity	4

Notes

The time complexity is based on the resulting substring. It does not depend on the size of the original string.
For small strings, the complexity will not change that much. In that case, we can consider the time complexity as O(1).

Signature

GETRANGE <key> <start_index> <end_index>

Usage

Get substring from a string value. The substring is obtained from the specified <key> and the offsets are defined by the <start_index> and <end_index>.

Notes

As the command “SUBSTR” is deprecated in Redis, so this “GETRANGE” command is a substitute for that command.

Arguments

Parameter	Description	Name	Type
<key>	Name of the key	key	key
<start_index>	Starting index of the substring	start	integer
<end_index>	Ending index of the substring	end	integer

Notes

Counting of the index starts from Zero(0).

Indexes can be positive or negative. A negative index means counting the index in reverse order (-1 index is the last element)

Return Value

Return value	Case for the return value	Type
Subtring from the start to the ending index	If the key is valid and indexes are correct	string
Blank string (“”)	In case of wrong/non-existing key. Or the provided indexes are wrong.	string
error	If data is not of string type	error

Notes

Both the start and end index are inclusive(included in the result substring).

Examples

Here are a few examples of the GETRANGE command usage-

# Redis GETRANGE command examples

# Set some string value for description key
127.0.0.1:6379> set description "some long string for GETRANGE testing"
OK

# Get substring from description from index 0 to 10
127.0.0.1:6379> getrange description 0 10
"some long s"

# Get substring from description from index 0 to 1
127.0.0.1:6379> getrange description 0 1
"so"

# Get substring from description from index 0 to -1
127.0.0.1:6379> getrange description 0 -1
"some long string for GETRANGE testing"

# Get substring from description from index 20 to -1
127.0.0.1:6379> getrange description 20 -1
" GETRANGE testing"

# Get substring from description from index -5 to -1
127.0.0.1:6379> getrange description -5 -1
"sting"

# Get substring from description from index 20 to 10
# It will return empty string as the starting index is of a later element
127.0.0.1:6379> getrange description 20 10
""

# Get substring from description from index -1 to -5
# It will return empty string as the starting index is of a later element
127.0.0.1:6379> getrange description -1 -5
""

# Get substring from description from index 10 to 2000000
# As last index is out of range so the result will stop at the end of the source string
127.0.0.1:6379> getrange description 10 2000000
"string for GETRANGE testing"

# Get substring from description from index 5 to 5
127.0.0.1:6379> getrange description 5 5
"l"

# Try to get substring from a key that is not set.
# Returns an empty string.
127.0.0.1:6379> getrange wrongkey 10 20
""

# Create a list
127.0.0.1:6379> lpush mylist abcd
(integer) 1

# Try to get a substring by index, from the list
# returns error
127.0.0.1:6379> getrange mylist 0 2
(error) WRONGTYPE Operation against a key holding the wrong kind of value

Notes

If the provided index is out of range, then the result is restricted to the maximum length of the string.

If the start index is larger(index of a later element), then the result will be an empty string. For example-
<start_index>: 20 and <end_index>: 10
or <start_index>: -1 and <end_index>:-5
If the key is not defined then result will be empty string.
If key data is not of type string then the following error message is returned-
(error) WRONGTYPE Operation against a key holding the wrong kind of value

Code Implementations

Here are the usage examples of the Redis GETRANGE command in different programming languages.

Go
NodeJS

Python
Ruby

// Redis GETRANGE command example in Golang

package main

import (
	"context"
	"fmt"

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

var rdb *redis.Client
var ctx context.Context

func init() {
	rdb = redis.NewClient(&redis.Options{
		Addr:     "localhost:6379",
		Username: "default",
		Password: "",
		DB:       0,
	})

	ctx = context.Background()
}

func main() {

	// Set some string value for description key
	// Command: set description "some long string for GETRANGE testing"
	// Result: OK
	setResult, err := rdb.Set(ctx, "description", "some long string for GETRANGE testing", 0).Result()

	if err != nil {
		fmt.Println("Command: set description \"some long string for GETRANGE testing\" | Error: " + err.Error())
	}

	fmt.Println("Command: set description \"some long string for GETRANGE testing\" | Result: " + setResult)

	// Get substring from description from index 0 to 10
	// Command:  getrange description 0 10
	// Result: "some long s"
	getRangeResult, err := rdb.GetRange(ctx, "description", 0, 10).Result()

	if err != nil {
		fmt.Println("Command: getrange description 0 10 | Error: " + err.Error())
	}

	fmt.Println("Command: getrange description 0 10 | Result: " + getRangeResult)

	// Get substring from description from index 0 to 1
	// Command:  getrange description 0 1
	// Result: "so"
	getRangeResult, err = rdb.GetRange(ctx, "description", 0, 1).Result()

	if err != nil {
		fmt.Println("Command: getrange description 0 1 | Error: " + err.Error())
	}

	fmt.Println("Command: getrange description 0 1 | Result: " + getRangeResult)

	// Get substring from description from index 0 to -1
	// Command:  getrange description 0 -1
	// Result: "some long string for GETRANGE testing"
	getRangeResult, err = rdb.GetRange(ctx, "description", 0, -1).Result()

	if err != nil {
		fmt.Println("Command: getrange description 0 -1 | Error: " + err.Error())
	}

	fmt.Println("Command: getrange description 0 -1 | Result: " + getRangeResult)

	// Get substring from description from index 20 to -1
	// Command:  getrange description 20 -1
	// Result: " GETRANGE testing"
	getRangeResult, err = rdb.GetRange(ctx, "description", 20, -1).Result()

	if err != nil {
		fmt.Println("Command: getrange description 20 -1 | Error: " + err.Error())
	}

	fmt.Println("Command: getrange description 20 -1 | Result: " + getRangeResult)

	// Get substring from description from index -5 to -1
	// Command:  getrange description -5 -1
	// Result: "sting"
	getRangeResult, err = rdb.GetRange(ctx, "description", -5, -1).Result()

	if err != nil {
		fmt.Println("Command: getrange description -5 -1 | Error: " + err.Error())
	}

	fmt.Println("Command: getrange description -5 -1 | Result: " + getRangeResult)

	// Get substring from description from index 20 to 10
	// It will return empty string as the starting index is of a later element
	// Command:  getrange description 20 10
	// Result: ""
	getRangeResult, err = rdb.GetRange(ctx, "description", 20, 10).Result()

	if err != nil {
		fmt.Println("Command: getrange description 20 10 | Error: " + err.Error())
	}

	fmt.Println("Command: getrange description 20 10 | Result: " + getRangeResult)

	// Get substring from description from index -1 to -5
	// It will return empty string as the starting index is of a later element
	// Command:  getrange description -1 -5
	// Result: ""
	getRangeResult, err = rdb.GetRange(ctx, "description", -1, -5).Result()

	if err != nil {
		fmt.Println("Command: getrange description -1 -5 | Error: " + err.Error())
	}

	fmt.Println("Command: getrange description -1 -5 | Result: " + getRangeResult)

	// Get substring from description from index 10 to 2000000
	// As last index is out of range so the // Result will stop at the end of the source string
	// Command:  getrange description 10 2000000
	// Result: "string for GETRANGE testing"
	getRangeResult, err = rdb.GetRange(ctx, "description", 10, 2000000).Result()

	if err != nil {
		fmt.Println("Command: getrange description 10 2000000 | Error: " + err.Error())
	}

	fmt.Println("Command: getrange description 10 2000000 | Result: " + getRangeResult)

	// Get substring from description from index 5 to 5
	// Command:  getrange description 5 5
	// Result: "l"
	getRangeResult, err = rdb.GetRange(ctx, "description", 5, 5).Result()

	if err != nil {
		fmt.Println("Command: getrange description 5 5 | Error: " + err.Error())
	}

	fmt.Println("Command: getrange description 5 5 | Result: " + getRangeResult)

	// Try to get substring from a key that is not set.
	// Returns an empty string.
	// Command:  getrange wrongkey 10 20
	// Result: ""
	getRangeResult, err = rdb.GetRange(ctx, "wrongkey", 10, 20).Result()

	if err != nil {
		fmt.Println("Command: getrange wrongkey 10 20 | Error: " + err.Error())
	}

	fmt.Println("Command: getrange wrongkey 10 20 | Result: " + getRangeResult)

	// Create a list
	// Command:  lpush mylist abcd
	// Result: (integer) 1
	listCommandResult, err := rdb.LPush(ctx, "mylist", "abcd").Result()

	if err != nil {
		fmt.Println("Command: lpush mylist abcd | Error: " + err.Error())
	}

	fmt.Printf("Command: lpush mylist abcd | Result: %v\n", listCommandResult)

	// Try to get a substring by index, from the list
	// Command:  getrange mylist 0 2
	// Result: (error) WRONGTYPE Operation against a key holding the wrong kind of value
	getRangeResult, err = rdb.GetRange(ctx, "mylist", 0, 10).Result()

	if err != nil {
		fmt.Println("Command: getrange mylist 0 2 | Error: " + err.Error())
	}

	fmt.Println("Command: getrange mylist 0 2 | Result: " + getRangeResult)

}

Output:

Command: set description "some long string for GETRANGE testing" | Result: OK

Command: getrange description 0 10 | Result: some long s

Command: getrange description 0 1 | Result: so

Command: getrange description 0 -1 | Result: some long string for GETRANGE testing

Command: getrange description 20 -1 | Result:  GETRANGE testing

Command: getrange description -5 -1 | Result: sting

Command: getrange description 20 10 | Result:

Command: getrange description -1 -5 | Result:

Command: getrange description 10 2000000 | Result: string for GETRANGE testing

Command: getrange description 5 5 | Result: l

Command: getrange wrongkey 10 20 | Result:

Command: lpush mylist abcd | Result: 1
Command: getrange mylist 0 2 | Error: WRONGTYPE Operation against a key holding the wrong kind of value
Command: getrange mylist 0 2 | Result:

Notes

Use “GetRange” method from redis-go module.
Signature of the method is-
GetRange(ctx context.Context, key string, start, end int64) *StringCmd

// Redis GETRANGE command example in JavaScript(NodeJS)

import { createClient } from 'redis';

// Create redis client
const redisClient = createClient({
    url: 'redis://default:@localhost:6379'
});

redisClient.on('error', err => console.log('Error while connecting to Redis', err));

// Connect Redis client
await redisClient.connect();

/**
 * Set some string value for description key
 *
 * Command: set description "some long string for GETRANGE testing"
 * Result: OK
 */
let commandResult = await redisClient.set("description", "some long string for GETRANGE testing");

console.log("Command: set description \"some long string for GETRANGE testing\" | Result: " + commandResult);

/**
 * Get substring from description from index 0 to 10
 *
 * Command:  getrange description 0 10
 * Result: "some long s"
 */
commandResult = await redisClient.getRange("description", 0, 10);

console.log("Command: getrange description 0 10 | Result: " + commandResult);

/**
 * Get substring from description from index 0 to 1
 *
 * Command:  getrange description 0 1
 * Result: "so"
 */
commandResult = await redisClient.getRange("description", 0, 1);

console.log("Command: getrange description 0 1 | Result: " + commandResult);

/**
 * Get substring from description from index 0 to -1
 *
 * Command:  getrange description 0 -1
 * Result: "some long string for GETRANGE testing"
 */
commandResult = await redisClient.getRange("description", 0, -1);

console.log("Command: getrange description 0 -1 | Result: " + commandResult);

/**
 * Get substring from description from index 20 to -1
 *
 * Command:  getrange description 20 -1
 * Result: " GETRANGE testing"
 */
commandResult = await redisClient.getRange("description", 20, -1);

console.log("Command: getrange description 20 -1 | Result: " + commandResult);

/**
 * Get substring from description from index -5 to -1
 * Command:  getrange description -5 -1
 * Result: "sting"
 */
commandResult = await redisClient.getRange("description", -5, -1);

console.log("Command: getrange description -5 -1 | Result: " + commandResult);

/**
 * Get substring from description from index 20 to 10
 * It will return empty string as the starting index is of a later element
 * Command:  getrange description 20 10
 * Result: ""
 */
commandResult = await redisClient.getRange("description", 20, 10);

console.log("Command: getrange description 20 10 | Result: " + commandResult);

/**
 * Get substring from description from index -1 to -5
 * It will return empty string as the starting index is of a later element
 * Command:  getrange description -1 -5
 * Result: ""
 */
commandResult = await redisClient.getRange("description", -1, -5);

console.log("Command: getrange description -1 -5 | Result: " + commandResult);

/**
 * Get substring from description from index 10 to 2000000
 * As last index is out of range so the * Result will stop at the end of the source string
 * Command:  getrange description 10 2000000
 * Result: "string for GETRANGE testing"
 */
commandResult = await redisClient.getRange("description", 10, 2000000);

console.log("Command: getrange description 10 2000000 | Result: " + commandResult);

/**
 * Get substring from description from index 5 to 5
 * Command:  getrange description 5 5
 * Result: "l"
 */
commandResult = await redisClient.getRange("description", 5, 5);

console.log("Command: getrange description 5 5 | Result: " + commandResult);

/**
 * Try to get substring from a key that is not set.
 * Returns an empty string.
 * Command:  getrange wrongkey 10 20
 * Result: ""
 */
commandResult = await redisClient.getRange("wrongkey", 10, 20);

console.log("Command: getrange wrongkey 10 20 | Result: " + commandResult);

/**
 * Create a list
 * Command:  lpush mylist abcd
 * Result: (integer) 1
 */
commandResult = await redisClient.lPush("mylist", "abcd");

console.log("Command: lpush mylist abcd | Result: " + commandResult);

/**
 * Try to get a substring by index, from the list
 * Command:  getrange mylist 0 2
 * Result: (error) WRONGTYPE Operation against a key holding the wrong kind of value
 */
try {
    commandResult = await redisClient.getRange("mylist", 0, 10);

    console.log("Command: getrange mylist 0 2 | Result: " + commandResult);
} catch (e) {
    console.log("Command: getrange mylist 0 2 | Error: " + e);
}

process.exit(0);

Output:

Command: set description "some long string for GETRANGE testing" | Result: OK

Command: getrange description 0 10 | Result: some long s

Command: getrange description 0 1 | Result: so

Command: getrange description 0 -1 | Result: some long string for GETRANGE testing

Command: getrange description 20 -1 | Result:  GETRANGE testing

Command: getrange description -5 -1 | Result: sting

Command: getrange description 20 10 | Result:

Command: getrange description -1 -5 | Result:

Command: getrange description 10 2000000 | Result: string for GETRANGE testing

Command: getrange description 5 5 | Result: l

Command: getrange wrongkey 10 20 | Result:

Command: lpush mylist abcd | Result: 1
Command: getrange mylist 0 2 | Error: Error: WRONGTYPE Operation against a key holding the wrong kind of value

Notes

Use method “getRange” from the package node-redis.

// Redis GETRANGE Command example in Java

import redis.clients.jedis.Jedis;
import redis.clients.jedis.JedisPool;

public class Getrange {
    public static void main(String[] args) {
        // Create connection pool
        JedisPool jedisPool = new JedisPool("localhost", 6379);

        try (Jedis jedis = jedisPool.getResource()) {

            /**
             * Set some string value for description key
             *
             * Command: set description "some long string for GETRANGE testing"
             * Result: OK
             */
            String setResult = jedis.set("description", "some long string for GETRANGE testing");

            System.out.println("Command: set description \"some long string for GETRANGE testing\" | Result: " + setResult);

            /**
             * Get substring from description from index 0 to 10
             *
             * Command:  getrange description 0 10
             * Result: "some long s"
             */
            String getRangeResult = jedis.getrange("description", 0, 10);

            System.out.println("Command: getrange description 0 10 | Result: " + getRangeResult);

            /**
             * Get substring from description from index 0 to 1
             *
             * Command:  getrange description 0 1
             * Result: "so"
             */
            getRangeResult = jedis.getrange("description", 0, 1);

            System.out.println("Command: getrange description 0 1 | Result: " + getRangeResult);

            /**
             * Get substring from description from index 0 to -1
             *
             * Command:  getrange description 0 -1
             * Result: "some long string for GETRANGE testing"
             */
            getRangeResult = jedis.getrange("description", 0, -1);

            System.out.println("Command: getrange description 0 -1 | Result: " + getRangeResult);

            /**
             * Get substring from description from index 20 to -1
             *
             * Command:  getrange description 20 -1
             * Result: " GETRANGE testing"
             */
            getRangeResult = jedis.getrange("description", 20, -1);

            System.out.println("Command: getrange description 20 -1 | Result: " + getRangeResult);

            /**
             * Get substring from description from index -5 to -1
             * Command:  getrange description -5 -1
             * Result: "sting"
             */
            getRangeResult = jedis.getrange("description", -5, -1);

            System.out.println("Command: getrange description -5 -1 | Result: " + getRangeResult);

            /**
             * Get substring from description from index 20 to 10
             * It will return empty string as the starting index is of a later element
             * Command:  getrange description 20 10
             * Result: ""
             */
            getRangeResult = jedis.getrange("description", 20, 10);

            System.out.println("Command: getrange description 20 10 | Result: " + getRangeResult);

            /**
             * Get substring from description from index -1 to -5
             * It will return empty string as the starting index is of a later element
             * Command:  getrange description -1 -5
             * Result: ""
             */
            getRangeResult = jedis.getrange("description", -1, -5);

            System.out.println("Command: getrange description -1 -5 | Result: " + getRangeResult);

            /**
             * Get substring from description from index 10 to 2000000
             * As last index is out of range so the * Result will stop at the end of the source string
             * Command:  getrange description 10 2000000
             * Result: "string for GETRANGE testing"
             */
            getRangeResult = jedis.getrange("description", 10, 2000000);

            System.out.println("Command: getrange description 10 2000000 | Result: " + getRangeResult);

            /**
             * Get substring from description from index 5 to 5
             * Command:  getrange description 5 5
             * Result: "l"
             */
            getRangeResult = jedis.getrange("description", 5, 5);

            System.out.println("Command: getrange description 5 5 | Result: " + getRangeResult);

            /**
             * Try to get substring from a key that is not set.
             * Returns an empty string.
             * Command:  getrange wrongkey 10 20
             * Result: ""
             */
            getRangeResult = jedis.getrange("wrongkey", 10, 20);

            System.out.println("Command: getrange wrongkey 10 20 | Result: " + getRangeResult);

            /**
             * Create a list
             * Command:  lpush mylist abcd
             * Result: (integer) 1
             */
            long listCommandResult = jedis.lpush("mylist", "abcd");

            System.out.println("Command: lpush mylist abcd | Result: " + listCommandResult);

            /**
             * Try to get a substring by index, from the list
             * Command:  getrange mylist 0 2
             * Result: (error) WRONGTYPE Operation against a key holding the wrong kind of value
             */
            try {
                getRangeResult = jedis.getrange("mylist", 0, 10);

                System.out.println("Command: getrange mylist 0 2 | Result: " + getRangeResult);
            } catch (Exception e) {
                System.out.println("Command: getrange mylist 0 2 | Error: " + e.getMessage());
            }

        }

        jedisPool.close();
    }
}

Output:

Command: set description "some long string for GETRANGE testing" | Result: OK

Command: getrange description 0 10 | Result: some long s

Command: getrange description 0 1 | Result: so

Command: getrange description 0 -1 | Result: some long string for GETRANGE testing

Command: getrange description 20 -1 | Result:  GETRANGE testing

Command: getrange description -5 -1 | Result: sting

Command: getrange description 20 10 | Result: 

Command: getrange description -1 -5 | Result: 

Command: getrange description 10 2000000 | Result: string for GETRANGE testing

Command: getrange description 5 5 | Result: l

Command: getrange wrongkey 10 20 | Result: 

Command: lpush mylist abcd | Result: 1
Command: getrange mylist 0 2 | Error: WRONGTYPE Operation against a key holding the wrong kind of value

Notes

Use method “getrange” from Jedis package.

Signature of the “getrange” is-
public String getrange(final String key, final long startOffset, final long endOffset)

// Redis GETRANGE command examples in C#

using StackExchange.Redis;

namespace Getrange
{
    internal class Program
    {
        static void Main(string[] args)
        {
            ConnectionMultiplexer redis = ConnectionMultiplexer.Connect("localhost");
            IDatabase rdb = redis.GetDatabase();

            /**
             * Set some string value for description key
             *
             * Command: set description "some long string for GETRANGE testing"
             * Result: OK
             */
            bool setResult = rdb.StringSet("description", "some long string for GETRANGE testing");

            Console.WriteLine("Command: set description \"some long string for GETRANGE testing\" | Result: " + setResult);

            /**
             * Get substring from description from index 0 to 10
             *
             * Command:  getrange description 0 10
             * Result: "some long s"
             */
            RedisValue getRangeResult = rdb.StringGetRange("description", 0, 10);

            Console.WriteLine("Command: getrange description 0 10 | Result: " + getRangeResult);

            /**
             * Get substring from description from index 0 to 1
             *
             * Command:  getrange description 0 1
             * Result: "so"
             */
            getRangeResult = rdb.StringGetRange("description", 0, 1);

            Console.WriteLine("Command: getrange description 0 1 | Result: " + getRangeResult);

            /**
             * Get substring from description from index 0 to -1
             *
             * Command:  getrange description 0 -1
             * Result: "some long string for GETRANGE testing"
             */
            getRangeResult = rdb.StringGetRange("description", 0, -1);

            Console.WriteLine("Command: getrange description 0 -1 | Result: " + getRangeResult);

            /**
             * Get substring from description from index 20 to -1
             *
             * Command:  getrange description 20 -1
             * Result: " GETRANGE testing"
             */
            getRangeResult = rdb.StringGetRange("description", 20, -1);

            Console.WriteLine("Command: getrange description 20 -1 | Result: " + getRangeResult);

            /**
             * Get substring from description from index -5 to -1
             * Command:  getrange description -5 -1
             * Result: "sting"
             */
            getRangeResult = rdb.StringGetRange("description", -5, -1);

            Console.WriteLine("Command: getrange description -5 -1 | Result: " + getRangeResult);

            /**
             * Get substring from description from index 20 to 10
             * It will return empty string as the starting index is of a later element
             * Command:  getrange description 20 10
             * Result: ""
             */
            getRangeResult = rdb.StringGetRange("description", 20, 10);

            Console.WriteLine("Command: getrange description 20 10 | Result: " + getRangeResult);

            /**
             * Get substring from description from index -1 to -5
             * It will return empty string as the starting index is of a later element
             * Command:  getrange description -1 -5
             * Result: ""
             */
            getRangeResult = rdb.StringGetRange("description", -1, -5);

            Console.WriteLine("Command: getrange description -1 -5 | Result: " + getRangeResult);

            /**
             * Get substring from description from index 10 to 2000000
             * As last index is out of range so the * Result will stop at the end of the source string
             * Command:  getrange description 10 2000000
             * Result: "string for GETRANGE testing"
             */
            getRangeResult = rdb.StringGetRange("description", 10, 2000000);

            Console.WriteLine("Command: getrange description 10 2000000 | Result: " + getRangeResult);

            /**
             * Get substring from description from index 5 to 5
             * Command:  getrange description 5 5
             * Result: "l"
             */
            getRangeResult = rdb.StringGetRange("description", 5, 5);

            Console.WriteLine("Command: getrange description 5 5 | Result: " + getRangeResult);

            /**
             * Try to get substring from a key that is not set.
             * Returns an empty string.
             * Command:  getrange wrongkey 10 20
             * Result: ""
             */
            getRangeResult = rdb.StringGetRange("wrongkey", 10, 20);

            Console.WriteLine("Command: getrange wrongkey 10 20 | Result: " + getRangeResult);

            /**
             * Create a list
             * Command:  lpush mylist abcd
             * Result: (integer) 1
             */
            long listCommandResult = rdb.ListLeftPush("mylist", "abcd");

            Console.WriteLine("Command: lpush mylist abcd | Result: " + listCommandResult);

            /**
             * Try to get a substring by index, from the list
             * Command:  getrange mylist 0 2
             * Result: (error) WRONGTYPE Operation against a key holding the wrong kind of value
             */
            try
            {
                getRangeResult = rdb.StringGetRange("mylist", 0, 10);

                Console.WriteLine("Command: getrange mylist 0 2 | Result: " + getRangeResult);
            }
            catch (Exception e)
            {
                Console.WriteLine("Command: getrange mylist 0 2 | Error: " + e.Message);
            }
        }
    }
}

Output:

Command: set description "some long string for GETRANGE testing" | Result: True

Command: getrange description 0 10 | Result: some long s

Command: getrange description 0 1 | Result: so

Command: getrange description 0 -1 | Result: some long string for GETRANGE testing

Command: getrange description 20 -1 | Result:  GETRANGE testing

Command: getrange description -5 -1 | Result: sting

Command: getrange description 20 10 | Result:

Command: getrange description -1 -5 | Result:

Command: getrange description 10 2000000 | Result: string for GETRANGE testing

Command: getrange description 5 5 | Result: l

Command: getrange wrongkey 10 20 | Result:

Command: lpush mylist abcd | Result: 1
Command: getrange mylist 0 2 | Error: WRONGTYPE Operation against a key holding the wrong kind of value

Notes

Use the method “StringGetRange” from StackExchange.Redis.
Signature of the method is-
RedisValue StringGetRange(RedisKey key, long start, long end, CommandFlags flags = CommandFlags.None)

<?php
// Redis GETRANGE command example in PHP

require 'vendor/autoload.php';

// Connect to Redis
$redisClient = new Predis\Client([
    'scheme' => 'tcp',
    'host' => 'localhost',
    'port' => 6379,
]);


/**
 * Set some string value for description key
 *
 * Command: set description "some long string for GETRANGE testing"
 * Result: OK
 */
$commandResult = $redisClient->set("description", "some long string for GETRANGE testing");

echo "Command: set description \"some long string for GETRANGE testing\" | Result: " . $commandResult . "\n";

/**
 * Get substring from description from index 0 to 10
 *
 * Command:  getrange description 0 10
 * Result: "some long s"
 */
$commandResult = $redisClient->getrange("description", 0, 10);

echo "Command: getrange description 0 10 | Result: " . $commandResult . "\n";

/**
 * Get substring from description from index 0 to 1
 *
 * Command:  getrange description 0 1
 * Result: "so"
 */
$commandResult = $redisClient->getrange("description", 0, 1);

echo "Command: getrange description 0 1 | Result: " . $commandResult . "\n";

/**
 * Get substring from description from index 0 to -1
 *
 * Command:  getrange description 0 -1
 * Result: "some long string for GETRANGE testing"
 */
$commandResult = $redisClient->getrange("description", 0, -1);

echo "Command: getrange description 0 -1 | Result: " . $commandResult . "\n";

/**
 * Get substring from description from index 20 to -1
 *
 * Command:  getrange description 20 -1
 * Result: " GETRANGE testing"
 */
$commandResult = $redisClient->getrange("description", 20, -1);

echo "Command: getrange description 20 -1 | Result: " . $commandResult . "\n";

/**
 * Get substring from description from index -5 to -1
 * Command:  getrange description -5 -1
 * Result: "sting"
 */
$commandResult = $redisClient->getrange("description", -5, -1);

echo "Command: getrange description -5 -1 | Result: " . $commandResult . "\n";

/**
 * Get substring from description from index 20 to 10
 * It will return empty string as the starting index is of a later element
 * Command:  getrange description 20 10
 * Result: ""
 */
$commandResult = $redisClient->getrange("description", 20, 10);

echo "Command: getrange description 20 10 | Result: " . $commandResult . "\n";

/**
 * Get substring from description from index -1 to -5
 * It will return empty string as the starting index is of a later element
 * Command:  getrange description -1 -5
 * Result: ""
 */
$commandResult = $redisClient->getrange("description", -1, -5);

echo "Command: getrange description -1 -5 | Result: " . $commandResult . "\n";

/**
 * Get substring from description from index 10 to 2000000
 * As last index is out of range so the * Result will stop at the end of the source string
 * Command:  getrange description 10 2000000
 * Result: "string for GETRANGE testing"
 */
$commandResult = $redisClient->getrange("description", 10, 2000000);

echo "Command: getrange description 10 2000000 | Result: " . $commandResult . "\n";

/**
 * Get substring from description from index 5 to 5
 * Command:  getrange description 5 5
 * Result: "l"
 */
$commandResult = $redisClient->getrange("description", 5, 5);

echo "Command: getrange description 5 5 | Result: " . $commandResult . "\n";

/**
 * Try to get substring from a key that is not set.
 * Returns an empty string.
 * Command:  getrange wrongkey 10 20
 * Result: ""
 */
$commandResult = $redisClient->getrange("wrongkey", 10, 20);

echo "Command: getrange wrongkey 10 20 | Result: " . $commandResult . "\n";

/**
 * Create a list
 * Command:  lpush mylist abcd
 * Result: (integer) 1
 */
$listCommandResult = $redisClient->lpush("mylist", ["abcd"]);

echo "Command: lpush mylist abcd | Result: " . $listCommandResult . "\n";

/**
 * Try to get a substring by index, from the list
 * Command:  getrange mylist 0 2
 * Result: (error) WRONGTYPE Operation against a key holding the wrong kind of value
 */
try {
    $commandResult = $redisClient->getrange("mylist", 0, 10);

    echo "Command: getrange mylist 0 2 | Result: " . $commandResult . "\n";
} catch (\Exception $e) {
    echo "Command: getrange mylist 0 2 | Error: " . $e->getMessage() . "\n";
}

Output:

Command: set description "some long string for GETRANGE testing" | Result: OK

Command: getrange description 0 10 | Result: some long s

Command: getrange description 0 1 | Result: so

Command: getrange description 0 -1 | Result: some long string for GETRANGE testing

Command: getrange description 20 -1 | Result:  GETRANGE testing

Command: getrange description -5 -1 | Result: sting

Command: getrange description 20 10 | Result:

Command: getrange description -1 -5 | Result:

Command: getrange description 10 2000000 | Result: string for GETRANGE testing

Command: getrange description 5 5 | Result: l

Command: getrange wrongkey 10 20 | Result:

Command: lpush mylist abcd | Result: 1
Command: getrange mylist 0 2 | Error: WRONGTYPE Operation against a key holding the wrong kind of value

Notes

Use the method “getrange” of predis.
Signature of the method is-
getrange(string $key, $start, $end): string

# Redis GETRANGE command example in Python

import redis
import time

# Create Redis client
redisClient = redis.Redis(host='localhost', port=6379,
                          username='default', password='',
                          decode_responses=True)


# Set some string value for description key
# Command: set description "some long string for GETRANGE testing"
# Result: OK
commandResult = redisClient.set(
    "description", "some long string for GETRANGE testing")

print("Command: set description \"some long string for GETRANGE testing\" | Result: {}".format(commandResult))

# Get substring from description from index 0 to 10
# Command:  getrange description 0 10
# Result: "some long s"
commandResult = redisClient.getrange("description", 0, 10)

print("Command: getrange description 0 10 | Result: {}".format(commandResult))

# Get substring from description from index 0 to 1
# Command:  getrange description 0 1
# Result: "so"
commandResult = redisClient.getrange("description", 0, 1)

print("Command: getrange description 0 1 | Result: {}".format(commandResult))

# Get substring from description from index 0 to -1
# Command:  getrange description 0 -1
# Result: "some long string for GETRANGE testing"
commandResult = redisClient.getrange("description", 0, -1)

print("Command: getrange description 0 -1 | Result: {}".format(commandResult))

# Get substring from description from index 20 to -1
# Command:  getrange description 20 -1
# Result: " GETRANGE testing"
commandResult = redisClient.getrange("description", 20, -1)

print("Command: getrange description 20 -1 | Result: {}".format(commandResult))

# Get substring from description from index -5 to -1
# Command:  getrange description -5 -1
# Result: "sting"
commandResult = redisClient.getrange("description", -5, -1)

print("Command: getrange description -5 -1 | Result: {}".format(commandResult))

# Get substring from description from index 20 to 10
# It will return empty string as the starting index is of a later element
# Command:  getrange description 20 10
# Result: ""
commandResult = redisClient.getrange("description", 20, 10)

print("Command: getrange description 20 10 | Result: {}".format(commandResult))

# Get substring from description from index -1 to -5
# It will return empty string as the starting index is of a later element
# Command:  getrange description -1 -5
# Result: ""
commandResult = redisClient.getrange("description", -1, -5)

print("Command: getrange description -1 -5 | Result: {}".format(commandResult))

# Get substring from description from index 10 to 2000000
# As last index is out of range so the # Result will stop at the end of the source string
# Command:  getrange description 10 2000000
# Result: "string for GETRANGE testing"
commandResult = redisClient.getrange("description", 10, 2000000)

print("Command: getrange description 10 2000000 | Result: {}".format(commandResult))

# Get substring from description from index 5 to 5
# Command:  getrange description 5 5
# Result: "l"
commandResult = redisClient.getrange("description", 5, 5)

print("Command: getrange description 5 5 | Result: {}".format(commandResult))

# Try to get substring from a key that is not set.
# Returns an empty string.
# Command:  getrange wrongkey 10 20
# Result: ""
commandResult = redisClient.getrange("wrongkey", 10, 20)

print("Command: getrange wrongkey 10 20 | Result: {}".format(commandResult))

# Create a list
# Command:  lpush mylist abcd
# Result: (integer) 1
listCommandResult = redisClient.lpush("mylist", "abcd")

print("Command: lpush mylist abcd | Result: {}".format(listCommandResult))

# Try to get a substring by index, from the list
# Command:  getrange mylist 0 2
# Result: (error) WRONGTYPE Operation against a key holding the wrong kind of value
try:
    commandResult = redisClient.getrange("mylist", 0, 10)

    print("Command: getrange mylist 0 2 | Result: {}".format(commandResult))
except Exception as error:
    print("Command: getrange mylist 0 2 | Error: ", error)

Output:

Command: set description "some long string for GETRANGE testing" | Result: True

Command: getrange description 0 10 | Result: some long s

Command: getrange description 0 1 | Result: so

Command: getrange description 0 -1 | Result: some long string for GETRANGE testing

Command: getrange description 20 -1 | Result:  GETRANGE testing

Command: getrange description -5 -1 | Result: sting

Command: getrange description 20 10 | Result:

Command: getrange description -1 -5 | Result:

Command: getrange description 10 2000000 | Result: string for GETRANGE testing

Command: getrange description 5 5 | Result: l

Command: getrange wrongkey 10 20 | Result:

Command: lpush mylist abcd | Result: 1
Command: getrange mylist 0 2 | Error:  WRONGTYPE Operation against a key holding the wrong kind of value

Notes

Use method “getrange” from redis-py.

Signature of the method is –
def getrange(self, key: KeyT, start: int, end: int) -> ResponseT

# Redis GETRANGE command example in Ruby

require 'redis'

redis = Redis.new(host: "localhost", port: 6379)


# Set some string value for description key
# Command: set description "some long string for GETRANGE testing"
# Result: OK
commandResult = redis.set("description", "some long string for GETRANGE testing")

print("Command: set description \"some long string for GETRANGE testing\" | Result: ", commandResult, "\n")

# Get substring from description from index 0 to 10
# Command:  getrange description 0 10
# Result: "some long s"
commandResult = redis.getrange("description", 0, 10)

print("Command: getrange description 0 10 | Result: ", commandResult, "\n")

# Get substring from description from index 0 to 1
# Command:  getrange description 0 1
# Result: "so"
commandResult = redis.getrange("description", 0, 1)

print("Command: getrange description 0 1 | Result: ", commandResult, "\n")

# Get substring from description from index 0 to -1
# Command:  getrange description 0 -1
# Result: "some long string for GETRANGE testing"
commandResult = redis.getrange("description", 0, -1)

print("Command: getrange description 0 -1 | Result: ", commandResult, "\n")

# Get substring from description from index 20 to -1
# Command:  getrange description 20 -1
# Result: " GETRANGE testing"
commandResult = redis.getrange("description", 20, -1)

print("Command: getrange description 20 -1 | Result: ", commandResult, "\n")

# Get substring from description from index -5 to -1
# Command:  getrange description -5 -1
# Result: "sting"
commandResult = redis.getrange("description", -5, -1)

print("Command: getrange description -5 -1 | Result: ", commandResult, "\n")

# Get substring from description from index 20 to 10
# It will return empty string as the starting index is of a later element
# Command:  getrange description 20 10
# Result: ""
commandResult = redis.getrange("description", 20, 10)

print("Command: getrange description 20 10 | Result: ", commandResult, "\n")

# Get substring from description from index -1 to -5
# It will return empty string as the starting index is of a later element
# Command:  getrange description -1 -5
# Result: ""
commandResult = redis.getrange("description", -1, -5)

print("Command: getrange description -1 -5 | Result: ", commandResult, "\n")

# Get substring from description from index 10 to 2000000
# As last index is out of range so the # Result will stop at the end of the source string
# Command:  getrange description 10 2000000
# Result: "string for GETRANGE testing"
commandResult = redis.getrange("description", 10, 2000000)

print("Command: getrange description 10 2000000 | Result: ", commandResult, "\n")

# Get substring from description from index 5 to 5
# Command:  getrange description 5 5
# Result: "l"
commandResult = redis.getrange("description", 5, 5)

print("Command: getrange description 5 5 | Result: ", commandResult, "\n")

# Try to get substring from a key that is not set.
# Returns an empty string.
# Command:  getrange wrongkey 10 20
# Result: ""
commandResult = redis.getrange("wrongkey", 10, 20)

print("Command: getrange wrongkey 10 20 | Result: ", commandResult, "\n")

# Create a list
# Command:  lpush mylist abcd
# Result: (integer) 1
listCommandResult = redis.lpush("mylist", "abcd")

print("Command: lpush mylist abcd | Result: ", listCommandResult, "\n")

# Try to get a substring by index, from the list
# Command:  getrange mylist 0 2
# Result: (error) WRONGTYPE Operation against a key holding the wrong kind of value
begin
    commandResult = redis.getrange("mylist", 0, 10)

    print("Command: getrange mylist 0 2 | Result: ", commandResult, "\n")
rescue => e
    print("Command: getrange mylist 0 2 | Error: ", e, "\n")
end

Output:

Command: set description "some long string for GETRANGE testing" | Result: OK

Command: getrange description 0 10 | Result: some long s

Command: getrange description 0 1 | Result: so

Command: getrange description 0 -1 | Result: some long string for GETRANGE testing

Command: getrange description 20 -1 | Result:  GETRANGE testing

Command: getrange description -5 -1 | Result: sting

Command: getrange description 20 10 | Result: 

Command: getrange description -1 -5 | Result: 

Command: getrange description 10 2000000 | Result: string for GETRANGE testing

Command: getrange description 5 5 | Result: l

Command: getrange wrongkey 10 20 | Result: 

Command: lpush mylist abcd | Result: 4
Command: getrange mylist 0 2 | Error: WRONGTYPE Operation against a key holding the wrong kind of value

Notes

Use method “getrange” from the redis-rb.
Signature of the “getrange” method is-
def getrange(key, start, stop)

Source Code

Use the following links to get the source code used in this article-

Source Code of	Source Code Link
Command Examples	GitHub
Golang Implementation	GitHub
NodeJS Implementation	GitHub
Java Implementation	GitHub
C# Implementation	GitHub
PHP Implementation	GitHub
Python Implementation	GitHub
Ruby Implementation	GitHub

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