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Cluster cluster addslots(集群 槽位) cluster count failure reports(集群计数失败报告) cluster countkeysinslot cluster delslots cluster failover cluster forget cluster getkeysinslot cluster info cluster keyslot(集群键槽) cluster meet cluster nodes(集群节点) cluster replicate(集群复制) cluster reset(集群重置) cluster saveconfig cluster set config epoch cluster setslot cluster slaves cluster slots readonly readwrite Connection auth echo ping quit select swapdb Geo geoadd geodist geohash geopos georadius georadiusbymember Hashes hdel hexists hget hgetall hincrby hincrbyfloat hkeys hlen hmget hmset hscan hset hsetnx hstrlen hvals HyperLogLog pfadd pfcount pfmerge Keys del dump exists expire expireat keys migrate move object persist pexpire pexpireat pttl randomkey rename renamenx restore scan sort touch ttl type unlink wait Lists blpop brpop brpoplpush lindex linsert llen lpop lpush lpushx lrange lrem lset ltrim rpop rpoplpush rpush rpushx Pub/Sub psubscribe publish pubsub punsubscribe subscribe unsubscribe Scripting eval evalsha script debug script exists script flush script kill script load Server bgrewriteaof bgsave client getname client kill client list client pause client reply client setname command command count command getkeys command info config get config resetstat config rewrite config set dbsize debug object debug segfault flushall flushdb info lastsave monitor role save shutdown slaveof slowlog time Sets sadd scard sdiff sdiffstore sinter sinterstore sismember smembers smove spop srandmember srem sscan sunion sunionstore Sorted Sets zadd zcard zcount zincrby zinterstore zlexcount zrange zrangebylex zrangebyscore zrank zrem zremrangebylex zremrangebyrank zremrangebyscore zrevrange zrevrangebylex zrevrangebyscore zrevrank zscan zscore zunionstore Strings append bitcount bitfield bitop bitpos decr decrby get getbit getrange getset incr incrby incrbyfloat mget mset msetnx psetex set setbit setex setnx setrange strlen Transactions discard exec multi unwatch watch
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EXISTS key [key ...]

自1.0.0起可用。

时间复杂度: O(1)

返回如果key存在。

自 Redis 3.0.3 以来,可以指定多个密钥而不是单个密钥。在这种情况下,它会返回现有密钥的总数。请注意,为单个键返回1或0只是可变参数使用的特例,因此该命令完全向后兼容。

用户应该知道,如果多次在参数中提及相同的现有密钥,它将被多次计数。所以如果somekey存在,EXISTS somekey somekey将返回2。

返回值

整数回复,具体为:

  • 1 如果密钥存在。

  • 0 如果密钥不存在。

自 Redis 3.0.3 以来,该命令接受可变数量的键并将返回值进行了概括:

  • 存在于指定为参数的键中的键的数量。键提及多次,现有计数多次。

例子

redis>  SET key1 "Hello" "OK" 

redis>  EXISTS key1 (integer) 1 

redis>  EXISTS nosuchkey (integer) 0 

redis>  SET key2 "World" "OK" 

redis>  EXISTS key1 key2 nosuchkey (integer) 2

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