If you’re getting an error that reads “ERR wrong number of arguments for ‘smembers’ command” in Redis, it’s because you’re calling the SMEMBERS command with the wrong number of arguments.

To fix this issue, make sure you’re passing the correct number of arguments. At the time of writing, the correct number of arguments for this command is one.

Example of Error

Here’s an example of code that produces the above error:

SMEMBERS animals Dog

Result:

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

In this case, I passed two arguments, but I should have passed just one.

We get the same error when we don’t pass any arguments:

SMEMBERS

Result:

ERR wrong number of arguments for 'smembers' command

Solution

To fix the issue, simply pass the correct number of arguments.

Example:

SMEMBERS animals

Result:

1) "Cat"
2) "Dog"
3) "Mouse"
4) "Zebra"

Here, I provided the correct number of arguments and we got the desired result without error.

At the time of writing, SMEMBERS accepts one argument. This argument is the key that contains the set that we’re trying to retrieve all members of. See the Redis documentation to check the latest specification for this command (in case anything changes after this article is published).