GETRANGE

The GETRANGE command in DiceDB is used to get a substring of a string, provided the start and end indices.

Syntax

GETRANGE key start end

Parameters

Parameter	Description	Type	Required
key	The name of the key containing the string.	String	Yes
start	The starting index of the required substring.	Integer	Yes
end	The ending index of the required substring.	Integer	Yes

Return values

Condition	Return Value
if key contains a valid string	a substring based on the start and end indices
if start is greater than end	an empty string is returned
if the end exceeds the length of the string present at key	the entire string is returned
if the start is greater than the length of the string	an empty string is returned.

Behaviour

• If the specified key does not exist, the GETRANGE command returns an empty string.
• If start is greater than end, the GETRANGE command returns an empty string.
• If start is not within the length of the string, the GETRANGE command returns an empty string.
• start and end can be negative which removed end + 1 characters from the other side of the string.
• Both start and end can be negative, which removes characters from the string, starting from the end + 1 position on the right.

Errors

1. Wrong type of value or key:

   • Error Message: (error) ERROR WRONGTYPE Operation against a key holding the wrong kind of value
   • Occurs when attempting to use the command on a key that contains a non-string value.

2. Invalid syntax or conflicting options:

   • Error Message: (error) ERROR wrong number of arguments for 'GETRANGE' command
   • If the number of arguments are not exactly equal to 4.

3. Invalid input type for start and end

   • Error Message: (error) ERROR value is not an integer or out of range
   • If start and end are not integers.

Example Usage

Basic Usage

Assume we have a string stored in foo

127.0.0.1:7379> SET foo apple
OK

127.0.0.1:7379> GETRANGE foo 1 3
"ppl"

127.0.0.1:7379> GETRANGE foo 0 -1
"apple"

127.0.0.1:7379> GETRANGE foo 0 -10
""

127.0.0.1:7379> GETRANGE foo 0 -2
"appl"

127.0.0.1:7379> GETRANGE foo 0 1001
"apple"

GETRANGE returns string representation of byte array stored in bitmap

127.0.0.1:7379> SETBIT bitmapkey 2 1
(integer) 0
127.0.0.1:7379> SETBIT bitmapkey 3 1
(integer) 0
127.0.0.1:7379> SETBIT bitmapkey 5 1
(integer) 0
127.0.0.1:7379> SETBIT bitmapkey 10 1
(integer) 0
127.0.0.1:7379> SETBIT bitmapkey 11 1
(integer) 0
127.0.0.1:7379> SETBIT bitmapkey 14 1
(integer) 0
127.0.0.1:7379> GETRANGE bitmapkey 0 -1
"42"

Invalid usage

Trying to use GETRANGE without giving the value

127.0.0.1:7379> GETRANGE foo
(error) ERROR wrong number of arguments for 'getrange' command

Trying to use GETRANGE on an invalid data type.

127.0.0.1:7379> LPUSH foo apple
127.0.0.1:7379> GETRANGE foo 0 5
(error) ERROR WRONGTYPE Operation against a key holding the wrong kind of value

127.0.0.1:7379> GETRANGE foo s e
(error) ERROR value is not an integer or out of range