EXISTS key [key ...]

Available since 1.0.0.

Time complexity: O(1)

Returns if key exists.

Since Redis 3.0.3 it is possible to specify multiple keys instead of a single one. In such a case, it returns the total number of keys existing. Note that returning 1 or 0 for a single key is just a special case of the variadic usage, so the command is completely backward compatible.

The user should be aware that if the same existing key is mentioned in the arguments multiple times, it will be counted multiple times. So if somekey exists, EXISTS somekey somekey will return 2.

*Return value

Integer reply, specifically:

  • 1 if the key exists.
  • 0 if the key does not exist.

Since Redis 3.0.3 the command accepts a variable number of keys and the return value is generalized:

  • The number of keys existing among the ones specified as arguments. Keys mentioned multiple times and existing are counted multiple times.

*Examples

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
redis>