Return the set cardinality (number of elements). If the key does not exist 0 is returned, like for empty sets. @param key @return Integer reply, specifically: the cardinality (number of elements) of the set as an integer.
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Return the set cardinality (number of elements). If the key does not exist 0 is returned, like for empty sets. @param key @return Integer reply, specifically: the cardinality (number of elements) of the set as an integer.