LSET command in redis

LSET key index value

Set the list element at index (see LINDEX for information about the index argument) with the new value. Out-of-range indexes will generate an error. 

Note that setting the first or last elements of the list is O(1).

TIME COMPLEXITY: O(N) (with N being the length of the list)

Similar to other list commands accepting indexes, the index can be negative to access elements starting from the end of the list. So -1 is the last element, -2 is the penultimate, and so forth.

RETURN VALUE: Status code reply.

Syntax:

LSET KEY_NAME INDEX VALUE

Example 1: When the key is present and the index is in the range.

redis:6379> LPUSH myList 100
(integer) 1
redis:6379> LSET myList 0 200
"OK"

Output

OK

Example 2: When the key is not present.

redis:6379> LSET myList 0 100
(error) no such key

Output

no such key

Example 3: When the index is out of range.

redis:6379> LPUSH myList 100
(integer) 1
redis:6379> LSET myList 1 100
(error) index out of range

Output

index out of range