ZADD command in redis

ZADD key score member

Add the specified member having the specified score to the sorted set stored at the key.

Note:

1. If a member is already a member of the sorted set the score is updated, and the element is reinserted in the right position to ensure sorting.

2. If the key does not exist a new sorted set with the specified member as a sole member is created.

3. If the key exists but does not hold a sorted set value an error is returned.

TIME COMPLEXITY: O(log(N)) with N being the number of elements in the sorted set

The score value can be the string representation of a double precision floating point number.

RETURN VALUE: Integer reply, specifically:

1 if the new element was added

0 if the element was already a member of the sorted set and the score was updated.

Syntax:

ZADD key score member

Example 1: When the score is a valid float value.

redis:6379> ZADD key 10.9 member
(integer) 1

Output

1

Example 2: When the score is not a valid float value.

redis:6379> ZADD key score member
(error) value is not a valid float

Output

(error) value is not a valid float