In Redis, we can use the SISMEMBER command to find out whether or not a set contains a given member.

Syntax

The syntax goes like this:

SISMEMBER key member

Example

Suppose we create the following set:

SADD animals Cat Dog Mouse

We can use the SISMEMBER command to find out whether our set contains a specified value:

SISMEMBER animals Dog

Result:

(integer) 1

In this case we get an integer reply of 1, which means that the set does contain the value.

Here’s what happens when the set doesn’t contain the value:

SISMEMBER animals Horse

Result:

(integer) 0

Here’s what happens when I pass a value that exists, but with a different case:

SISMEMBER animals dog

Result:

(integer) 0

No match.

Non-Existent Key

Here’s what happens when I pass a key that doesn’t exist:

SISMEMBER oops dog

Result:

(integer) 0

Passing the Wrong Number of Arguments

Passing the wrong number of arguments results in an error:

SISMEMBER animals Dog Mouse

Result:

(error) ERR wrong number of arguments for 'sismember' command