Set 中的值是不能重复的

应用场景：共同关注

添加

插入值

sadd

127.0.0.1:6379> sadd set hello
(integer) 1
127.0.0.1:6379> sadd set world
(integer) 1
127.0.0.1:6379> sadd set world # 插入了重复值，没有生效
(integer) 0
127.0.0.1:6379> smembers set
1) "world"
2) "hello"

查看

查看所有元素

smembers

127.0.0.1:6379> smembers set
1) "world"
2) "hello"

判断元素是否存在

sismember

127.0.0.1:6379> SMEMBERS set
1) "world"
2) "hello"
127.0.0.1:6379> sismember set hello # 存在返回 1
(integer) 1
127.0.0.1:6379> sismember set hello1 # 不存在返回 0
(integer) 0

获取元素个数

scard

127.0.0.1:6379> scard set
(integer) 2

获取随机元素

srandmember

127.0.0.1:6379> smembers set
1) "world"
2) "hello"
127.0.0.1:6379> srandmember set
"world"
127.0.0.1:6379> srandmember set
"hello"

获取两个集合的差集

sdiff

127.0.0.1:6379> smembers set1
1) "b"
2) "a"
127.0.0.1:6379> smembers set2
1) "b"
2) "c"
127.0.0.1:6379> sdiff set1 set2 # 取 set1 对于 set2 的差集
1) "a"
127.0.0.1:6379> sdiff set2 set1 # 取 set2 对于 set1 的差集
1) "c"

获取两个集合的交集

sinter

127.0.0.1:6379> smembers set1
1) "b"
2) "a"
127.0.0.1:6379> smembers set2
1) "b"
2) "c"
127.0.0.1:6379> sinter set1 set2 # 取 set1 和 set2 的交集
1) "b"

可以用来获取共同关注。

获取两个集合的并集

sunion

127.0.0.1:6379> smembers set1
1) "b"
2) "a"
127.0.0.1:6379> smembers set2
1) "b"
2) "c"
127.0.0.1:6379> sunion set1 set2
1) "b"
2) "c"
3) "a"

移除

移除指定元素

srem

127.0.0.1:6379> srem set world
(integer) 1
127.0.0.1:6379> smembers set
1) "hello"

随机移除元素

spop

127.0.0.1:6379> smembers set
1) "world"
2) "hello"
127.0.0.1:6379> spop set
"world"

移动

移动指定元素到其他集合

smove

127.0.0.1:6379> smembers set
1) "hello"
127.0.0.1:6379> smove set set1 hello # 移动 set 中的 hello 到 set1 中（set1 是存在的）
(integer) 1
127.0.0.1:6379> smembers set1
1) "hello"
2) "world"
127.0.0.1:6379> smembers set
(empty array)
127.0.0.1:6379> smove set1 set2 hello # 移动 set1 中的 hello 到 set2 中（set2 不存在则创建）
(integer) 1
127.0.0.1:6379> smembers set2
1) "hello"