{ "ZCARD": { "summary": "Returns the number of members in a sorted set.", "complexity": "O(1)", "group": "sorted_set", "since": "1.2.0", "arity": 2, "function": "zcardCommand", "command_flags": [ "READONLY", "FAST" ], "acl_categories": [ "SORTEDSET" ], "key_specs": [ { "flags": [ "RO" ], "begin_search": { "index": { "pos": 1 } }, "find_keys": { "range": { "lastkey": 0, "step": 1, "limit": 0 } } } ], "reply_schema": { "description": "The cardinality (number of elements) of the sorted set, or 0 if key does not exist", "type": "integer" }, "arguments": [ { "name": "key", "type": "key", "key_spec_index": 0 } ] } }