func (this *Output) RecommendItemForUser(userId string) ([]string, error) {
	arrayInterface, err := redis.Values(redisClient.Do("ZREVRANGE", this.cSet.recommendedItem(userId), 0, this.recNum))
	if err != nil {
		return nil, err
	}
	return this.toStrings(arrayInterface), err
}
get recommend items for user
package gocommend
import "github.com/garyburd/redigo/redis"
type Output struct {
	recNum int
	cSet   collectionSet
}
func (this *Output) Init(collection string, recNum int) error {
	if collection == "" {
		return gocommendError{emptyCollection}
	}
	this.recNum = recNum - 1
	this.cSet = collectionSet{}
	this.cSet.init(collection)
	return nil
}
func (this *Output) toStrings(arrayInterface []interface{}) (strings []string) {
	for _, rs := range arrayInterface {
		s, _ := redis.String(rs, nil)
		strings = append(strings, s)
	}
	return
}