redis:set集合类型的操作（无序集合）

1. set集合类型的操作（无序集合）

集合具有无序性（没有顺序）、确定性（描述是确定的）、唯一性（没有重复的元素）

1.1. sadd key member [member ...]

语法：sadd key member [member ...]

作用：往集合key中添加元素

返回值：添加元素的个数

例：

127.0.0.1:6379> sadd fruit apple banana pear

(integer) 3

127.0.0.1:6379> sadd num 1 1

(integer) 1

1.2. smembers key

语法：smembers key

作用：返回集合key中所有的元素

例：

127.0.0.1:6379> smembers fruit

1) "pear"

2) "banana"

3) "apple"

127.0.0.1:6379> smembers num

1) "1"

1.3. srandmember key [count]

语法：srandmember key [count]

作用：返回集合key中随机的1个元素

例：

127.0.0.1:6379> smembers letter

1) "d"

2) "g"

3) "c"

4) "e"

5) "a"

127.0.0.1:6379> srandmember letter

"e"

127.0.0.1:6379> srandmember letter

"c"

127.0.0.1:6379> srandmember letter

"a"

127.0.0.1:6379> srandmember letter 2

1) "c"

2) "e"

127.0.0.1:6379> srandmember letter 3

1) "c"

2) "e"

3) "a"

127.0.0.1:6379> smembers letter

1) "d"

2) "g"

3) "c"

4) "e"

5) "a"

1.4. srem key member [member ...]

语法：srem key member [member ...]

作用：删除集合key中的member [member...]元素

返回值：忽略不存在的元素后，真正删除掉的元素的个数

例：

127.0.0.1:6379> smembers num

1) "1"

127.0.0.1:6379> srem num 1

(integer) 1

127.0.0.1:6379> smembers num

(empty list or set)

127.0.0.1:6379> srem fruit pear

(integer) 1

127.0.0.1:6379> smembers fruit

1) "banana"

2) "apple"

1.5. spop key [count]

语法：spop key [count]

作用：返回并删除集合key中1个随机的元素

例：

127.0.0.1:6379> sadd letter a b c d e f g

(integer) 7

127.0.0.1:6379> smembers letter

1) "c"

2) "d"

3) "g"

4) "b"

5) "e"

6) "a"

7) "f"

127.0.0.1:6379> spop letter

"b"

127.0.0.1:6379> smembers letter

1) "d"

2) "g"

3) "c"

4) "e"

5) "a"

6) "f"

127.0.0.1:6379> spop letter

"f"

127.0.0.1:6379> smembers letter

1) "d"

2) "g"

3) "c"

4) "e"

5) "a"

案例：

spop是返回并删除一个随机的元素，所以可以用来做抽奖，第一次spop出的可以作为第一名（一等奖），第二次spop出的可以作为第二名（二等奖）...

1.6. sismember key member

语法：sismember key member

作用：判断member是否是集合key中的元素

返回值：是返回1；不是返回0

例：

127.0.0.1:6379> smembers letter

1) "d"

2) "g"

3) "c"

4) "e"

5) "a"

127.0.0.1:6379> sismember letter a

(integer) 1

127.0.0.1:6379> sismember letter k

(integer) 0

127.0.0.1:6379> sismember letter 0

(integer) 0

1.7. scard key

语法：scard key

作用：返回集合key中元素的个数

例：

127.0.0.1:6379> smembers letter

1) "d"

2) "g"

3) "c"

4) "e"

5) "a"

127.0.0.1:6379> scard letter

(integer) 5

1.8. sinter key [key ...]

语法：sinter key [key ...]

作用：求出key [key ...]几个集合中的交集，并返回

例：

127.0.0.1:6379> sadd lisa c python java

(integer) 3

127.0.0.1:6379> sadd wang english python php

(integer) 3

127.0.0.1:6379> sadd poly python redis c++

(integer) 3

127.0.0.1:6379> sinter lisa wang poly

1) "python"

127.0.0.1:6379> sadd tom python java php redis

(integer) 4

127.0.0.1:6379> sinter tom poly

1) "redis"

2) "python"

1.9. sinterstore destination key [key ...]

语法：sinterstore destination key [key ...]

作用：求出key [key ...]几个集合中的交集，并赋给destination或存储在destination中

返回值：返回真正存储到destination中的元素的个数

例：

127.0.0.1:6379> smembers lisa

1) "python"

2) "java"

3) "c"

127.0.0.1:6379> smembers poly

1) "c++"

2) "redis"

3) "python"

127.0.0.1:6379> smembers tom

1) "redis"

2) "php"

3) "python"

4) "java"

127.0.0.1:6379> sinterstore lisa_tom lisa tom

(integer) 2

127.0.0.1:6379> smembers lisa_tom

1) "python"

2) "java"

1.10. sunion key [key ...]

语法：sunion key [key ...]

作用：求出key [key ...]几个集合的并集，并返回

例：

127.0.0.1:6379> sadd lisa c python java

(integer) 3

127.0.0.1:6379> sadd wang english python php

(integer) 3

127.0.0.1:6379> sadd poly python redis c++

(integer) 3

127.0.0.1:6379> sunion lisa wang

1) "python"

2) "c"

3) "java"

4) "php"

5) "english"

127.0.0.1:6379> sadd tom python java php redis

(integer) 4

127.0.0.1:6379> sunion lisa wang tom poly

1) "php"

2) "c"

3) "c++"

4) "redis"

5) "python"

6) "english"

7) "java"

1.11. sdiff key [key ...]

语法：sdiff key [key ...]

作用：求出key与[key ...]的差集

例：

127.0.0.1:6379> smembers lisa

1) "python"

2) "java"

3) "c"

127.0.0.1:6379> smembers tom

1) "redis"

2) "php"

3) "python"

4) "java"

127.0.0.1:6379> sdiff lisa tom

1) "c"

127.0.0.1:6379> sdiff tom lisa

1) "redis"

2) "php"

127.0.0.1:6379> smembers poly

1) "c++"

2) "redis"

3) "python"

127.0.0.1:6379> sdiff tom lisa poly

1) "php"