Redis Srandmember Command
The Redis Srandmember command is used to return a random element from a set.
Starting from Redis 2.6, the Srandmember command accepts an optional count parameter:
If count is positive and less than the set's cardinality, the command returns an array containing count distinct elements. If count is greater than or equal to the set's cardinality, the entire set is returned.
If count is negative, the command returns an array where elements may be repeated, and the array's length is the absolute value of count.
This operation is similar to SPOP, but while SPOP removes and returns a random element from the set, Srandmember only returns a random element without modifying the set.
Syntax
The basic syntax of the redis Srandmember command is as follows:
redis 127.0.0.1:6379> SRANDMEMBER KEY [count]
Available Versions
= 1.0.0
Return Value
When only the set key is provided, it returns a single element; if the set is empty, it returns nil. If the count parameter is provided, it returns an array; if the set is empty, it returns an empty array.
Example
redis 127.0.0.1:6379> SADD myset1 "hello"
(integer) 1
redis 127.0.0.1:6379> SADD myset1 "world"
(integer) 1
redis 127.0.0.1:6379> SADD myset1 "bar"
(integer) 1
redis 127.0.0.1:6379> SRANDMEMBER myset1
"bar"
redis 127.0.0.1:6379> SRANDMEMBER myset1 2
1) "hello"
2) "world"