set 是string类型的无序集合(元素不重复)。2的32次方
hashtable实现
set操作:
sadd set1 hello
sadd set1 hello
sadd set1 world
sadd set1 world
smembers set1
srem set1 hello
smembers set1
sadd set2 world0
sadd set2 world1
sadd set2 world2
spop set2 : 随机返回并删除一个元素
smembers set2
sadd set3 world0
sadd set3 world1
sadd set3 world2
smembers set3
sdiff set3 set2 : 差集
sdiff set2 set3 : 差集
sdiffstore set4 set3 set2 :差集存在set4
smembers set4
sinter set2 set3 :交集
sinterstore set5 set3 set2:交集存在set5
smembers set5
sunion set1 set2 :并集
sunionstore set6 set1 set2 : 并集存于set6
smembers set6
smove set3 set7 world1
smembers set3
smembers set7
scard set3 :元素个数
sismember set3 world1 :是否是成员元素
srandmember set6 :随机返回一个元素
操作结果见下图:
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