Method SCard

tx_set.go:235–249

SCard returns the set cardinality (number of elements) of the set stored in the bucket at given bucket and key.

(bucket string, key []byte)

// SCard returns the set cardinality (number of elements) of the set stored in the bucket at given bucket and key.
func (tx *Tx) SCard(bucket string, key []byte) (int, error) {
	if err := tx.checkTxIsClosed(); err != nil {
		return 0, err
	}
	b, err := tx.db.bucketMgr.GetBucket(DataStructureSet, bucket)
	if err != nil {
		return 0, err
	}
	bucketId := b.Id
	if set, ok := tx.db.Index.Set.exist(bucketId); ok {
		return set.SCard(string(key)), nil
	}

	return 0, ErrBucketNotFound
}

// SDiffByOneBucket returns the members of the set resulting from the difference
// between the first set and all the successive sets in one bucket.