ZRANDMEMBER key [count [WITHSCORES]]
- Available since:
- Time complexity:
- O(N) where N is the number of members returned
- ACL categories:
When called with just the
key argument, return a random element from the sorted set value stored at
If the provided
count argument is positive, return an array of distinct elements.
The array's length is either
count or the sorted set's cardinality (
ZCARD), whichever is lower.
If called with a negative
count, the behavior changes and the command is allowed to return the same element multiple times.
In this case, the number of returned elements is the absolute value of the specified
WITHSCORES modifier changes the reply so it includes the respective scores of the randomly selected elements from the sorted set.
Specification of the behavior when count is passed
count argument is a positive value this command behaves as follows:
- No repeated elements are returned.
countis bigger than the cardinality of the sorted set, the command will only return the whole sorted set without additional elements.
- The order of elements in the reply is not truly random, so it is up to the client to shuffle them if needed.
count is a negative value, the behavior changes as follows:
- Repeating elements are possible.
countelements, or an empty array if the sorted set is empty (non-existing key), are always returned.
- The order of elements in the reply is truly random.