SADD
Syntax
1. SADD key member [member ...]
Time complexity: O(1) for each element added, so O(N) to add N elements when the command is called with multiple arguments.
Add the specified members to the set stored at key. Specified members that are already a member of this set are ignored. If key does not exist, a new set is created before adding the specified members.
An error is returned when the value stored at key is not a set.
Return
Integer reply: the number of elements that were added to the set, not including all the elements already present in the set.
Examples
1. dragonfly> SADD myset "Hello"
2. (integer) 1
3. dragonfly> SADD myset "World"
4. (integer) 1
5. dragonfly> SADD myset "World"
6. (integer) 0
7. dragonfly> SMEMBERS myset
8. 1) "Hello"
9. 2) "World"
