HRANDFIELD key [count [WITHVALUES]]
@read
@hash
@slow
When called with just the key
argument, return a random field from the hash value stored at key
.
If the provided count
argument is positive, return an array of distinct fields.
The array’s length is either count
or the hash’s number of fields (HLEN
), whichever is lower.
If called with a negative count
, the behavior changes and the command is allowed to return the same field multiple times.
In this case, the number of returned fields is the absolute value of the specified count
.
The optional WITHVALUES
modifier changes the reply so it includes the respective values of the randomly selected hash fields.
@return
@bulk-string-reply: without the additional count
argument, the command returns a Bulk Reply with the randomly selected field, or nil
when key
does not exist.
@array-reply: when the additional count
argument is passed, the command returns an array of fields, or an empty array when key
does not exist.
If the WITHVALUES
modifier is used, the reply is a list fields and their values from the hash.
@examples
redis> HMSET coin heads obverse tails reverse edge null
TBD
redis> HRANDFIELD coin
TBD
redis> HRANDFIELD coin
TBD
redis> HRANDFIELD coin -5 WITHVALUES
Specification of the behavior when count is passed
When the count
argument is a positive value this command behaves as follows:
- No repeated fields are returned.
- If
count
is bigger than the number of fields in the hash, the command will only return the whole hash without additional fields. - The order of fields in the reply is not truly random, so it is up to the client to shuffle them if needed.
When the count
is a negative value, the behavior changes as follows:
- Repeating fields are possible.
- Exactly
count
fields, or an empty array if the hash is empty (non-existing key), are always returned. - The order of fields in the reply is truly random.