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ZCARD

Returns the number of elements in the sorted set stored at the specified key.

Syntax​

ZCARD key

Parameters​

  • key: The name of the sorted set.

Details​

  • Available since: 1.2.0
  • Time complexity: O(1)
  • ACL categories: @read, @sortedset, @fast

If the key does not exist, ZCARD returns 0, as an empty sorted set is considered to be of size 0.

Example​

Assume we have a sorted set called myzset with three members:

ZADD myzset 1 "member1" 2 "member2" 3 "member3"

To get the number of elements in myzset:

ZCARD myzset

This will return:

(integer) 3

Edge Cases​

  • If the specified key does not exist, ZCARD will return 0.
  • If the specified key exists but is not a sorted set, an error is returned.

RESP2/RESP3 Reply​

  • Integer reply: the number of elements in the sorted set.