[Redis Chapter 7] Set

標籤：set   redis   

Set類型是一個沒有排序的集合，可以在該類型那個執行添加、刪除或判斷某一元素是否存在等操作。由於Redis的內部是使用值為空白的hash table實現的，所以操作的時間複雜度為O(1), 最多儲存2^32-1個字串。

Set集合中不允許出現重複的元素，和List類型相比，Set類型在功能上另一個優勢是可以進行並集，交集，差集運算。

sadd

129.223.248.154:6379> sadd students tim
(integer) 1
129.223.248.154:6379> sadd students tim ben
(integer) 1

srem

129.223.248.154:6379> srem student tim
(integer) 0
129.223.248.154:6379> srem students tim
(integer) 1

smembers、sismember

129.223.248.154:6379> smembers students
1) "ben"
129.223.248.154:6379> sismember students ben
(integer) 1
129.223.248.154:6379> sismember students tim
(integer) 0

sdiff 差集

129.223.248.154:6379> sadd setDiffA 1 2 3
(integer) 3
129.223.248.154:6379> sadd setDiffB 2 3 4
(integer) 3
129.223.248.154:6379> sdiff setDiffA setDiffB
1) "1"

sinter 交集

129.223.248.154:6379> sadd setInterA 1 2 3
(integer) 3
129.223.248.154:6379> sadd setInterB 2 3 4
(integer) 3
129.223.248.154:6379> sinter setInterA setInterB
1) "2"
2) "3"

sunion 並集

129.223.248.154:6379> sadd setUnionA 1 2 3
(integer) 3
129.223.248.154:6379> sadd setUnionB 2 4 6
(integer) 3
129.223.248.154:6379> sunion setUnionA setUnionB
1) "1"
2) "2"
3) "3"
4) "4"
5) "6"

scard 集合總數

129.223.248.154:6379> scard students
(integer) 1
129.223.248.154:6379> smembers students
1) "ben"
129.223.248.154:6379> srandmember students
"ben"
129.223.248.154:6379> sadd students mike
(integer) 1
129.223.248.154:6379> srandmember students
"ben"
129.223.248.154:6379> srandmember students
"mike"
129.223.248.154:6379> srandmember students
"mike"
129.223.248.154:6379> sadd memebrs a b c
(integer) 3
129.223.248.154:6379> srandmember students 2
1) "ben"
2) "mike"

srandmember

129.223.248.154:6379> sadd letters a b c
(integer) 3
129.223.248.154:6379> srandmember letters 2
1) "b"
2) "c"

spop

129.223.248.154:6379> spop letters
"b"
129.223.248.154:6379> smembers letters
1) "a"
2) "c"
129.223.248.154:6379>

本文出自 “軟體設計與開發” 部落格，請務必保留此出處http://yuanzhitang.blog.51cto.com/2769219/1789613

[Redis Chapter 7] Set