EXISTS key [key …]

Time complexity: O(1)

Returns if 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.

, specifically:

• if the key exists.

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"

redis> EXISTS nosuchkey

redis> SET key2 "World"

redis> EXISTS key1 key2 nosuchkey