Redis系列-key相关主要操作函数
这篇blog主要总结下，redis中跟key相关的常用函数
1）keys www.zzzyk.com
语法：keys pattern
解释：查找所有匹配指定模式pattern的key
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[root@xsf001 ~]# redis-cli
redis 127.0.0.1:6379> keys * #所有key
1) "score"
2) "stu"
3) "score1"
4) "dest"
5) "lst.user"
6) "lst.tect"
redis 127.0.0.1:6379> keys scor?
1) "score"
redis 127.0.0.1:6379> keys scor[ee1]
1) "score"
2)randomkey
语法：randomkey
解释：返回一个随机key
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redis 127.0.0.1:6379> randomkey
"score"
redis 127.0.0.1:6379> randomkey
"list.user"
3）exists
语法：exists key
解释：判断一个key是否存在
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redis 127.0.0.1:6379> exists score #key存在 返回1
(integer) 1
redis 127.0.0.1:6379> exists scorefda #key不存在 返回0
(integer) 0
4）type
语法：type key
解释：返回key所存储的值类型，返回值：none【key不存在】，string，list ，set， zset和hash
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redis 127.0.0.1:6379> type score
zset
redis 127.0.0.1:6379> type lst.user
list
5）expire
语法：expire key seconds
解释：设置key的生存时间，单位是秒，当key过期时，会被自动删除
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redis 127.0.0.1:6379> expire dest 30
(integer) 1
redis 127.0.0.1:6379> expire dest1 30 # key不存在
(integer) 0
6）ttl
语法： ttl key
解释：得到key能存活时间，如果key不存在或没有设置生存时间时，返回-1
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redis 127.0.0.1:6379> expire diff 100
(integer) 1
redis 127.0.0.1:6379> ttl diff
(integer) 94
redis 127.0.0.1:6379> ttl diff
(integer) 92
7）persist
语法：persist key
解释：移除给定key的生存时间
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redis 127.0.0.1:6379> ttl diff
(integer) 28
redis 127.0.0.1:6379> persist diff
(integer) 1
redis 127.0.0.1:6379> ttl diff
(integer) -1
8）rename
语法：rename key newkey
解释：将key改名为newkey
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redis 127.0.0.1:6379> smembers diff
1) "zhangsan01"
redis 127.0.0.1:6379> rename diff diff01
OK
redis 127.0.0.1:6379> smembers diff
(empty list or set)
redis 127.0.0.1:6379> smembers diff01
1) "zhangsan01"
redis 127.0.0.1:6379> rename diff diff01
(error) ERR no such key
注意：当key和newkey相同或key不存在时，返回错误;当newkey已存在时，rename将覆盖旧值。
9）renamenx
语法：renamenx key newkey
解释：当且仅当newkey不存在时，改名key
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redis 127.0.0.1:6379> renamenx diff01 stu #stu存在
(integer) 0
redis 127.0.0.1:6379> renamenx diff01 diff #diff不存在
(integer) 1
10）del
语法：del key [key ...]
解释：删除一个或多个key
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redis 127.0.0.1:6379> del score1
(integer) 1
redis 127.0.0.1:6379> del union diff aa #key aa 不存在
(integer) 2
11）move
语法：move key db
解释：将key移动到指定db
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redis 127.0.0.1:6379> smembers stu #默认0
1) "zhangsan01"
2) "wangwu"
redis 127.0.0.1:6379> move stu 1 #移动到 1
(integer) 1
redis 127.0.0.1:6379> smembers stu
(empty list or set)
redis 127.0.0.1:6379> select 1 #选择db 1
OK
redis 127.0.0.1:6379[1]> smembers stu
1) "zhangsan01"
2) "wangwu"
12）sort
语法：sort key [BY pattern] [LIMIT offset count] [GET pattern [GET pattern ...]] [ASC|DESC] [ALPHA] [STORE destination]
解释：返回或保持给定列表，集合，有序集合key中经过排序的元素
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redis 127.0.0.1:6379> sort lst.tech limit 0 2 alpha desc #按字符集排序
1) "tec06"
2) "tec05"
redis 127.0.0.1:6379> sort lst.stud
1) "1"
2) "2"
3) "3"
redis 127.0.0.1:6379> sort lst.stud desc
1) "3"
2) "2"
3) "1"
redis 127.0.0.1:6379> keys stu.*
1) "stu.name.2"
2) "stu.name.3"
3) "stu.level.1"
4) "stu.level.2"
5) "stu.level.3"
6) "stu.name.1"
redis 127.0.0.1:6379> sort lst.stud by stu.level.* desc get stu.level.* get stu.name.*
1) "3"
2) "admin"
3) "2"
4) "joe"
5) "1"
6) "jim"
redis 127.0.0.1:6379> sort lst.stud by stu.level.* asc get stu.name.*
1) "jim"
2) "joe"
3) "admin"
sort虽然很“厉害”，但尽量不要让redis服务器来sort大量的数据。可以通过设定阀值减少要sort的数据，或把排序操作向前移，在web服务器或各个应用上来sort。
