如何从地图中检索价值 - 去朗? [英] How to retrieve value from map - go lang?
问题描述
我正在与 mgo
一起使用MongoDB和Go。我有以下代码:
func查找(collectionName,dbName字符串,查询接口{})(result [] interface {} ,错误){
collection:= session.DB(dbName).C(collectionName)
err = collection.Find(query).All(& result)
return result,err
$ b func GetTransactionID()(id interface {},err error){
query:= bson.M {}
transId,err:= Find( transactionId,dbName,query)
for key,value:= range transId {
fmt.Println(k:,key,v:,value)
}
$ / code>
输出:
k:0 v:map [_id:ObjectIdHex(536887c199b6d0510964c35b)transId:A000000000]
我需要获取 _id $ c $从
Find
中返回的映射值中创建c>和 transId
。我怎么能这样做?
我只是猜测,但如果你只是想检索所有 Transaction 文件并打印它们 - 这里是如何:
鉴于你有一个 struct
,它代表您的集合的文档例如:
类型事务结构{
Id bson.ObjectId`bson:_ id`
TransactionId字符串`bson:transId`
}
您可以获取全部使用MongoDB驱动程序(mgo)的文档:
var transactions [] Transaction
err = c.Find(bson .M {})。所有(&交易)
//处理err
用于索引,transaction:= range transactions {
fmt.Printf(%d:%+ v \ n,index,transaction)
}
添加(通用解决方案)
好的,在您提供了一些更多的洞察之后,这可能是没有您的通用解决方案唱一个结构。尝试编入BSON文档 bson.M
(未测试):
var data [] bson.M
err:= c.Find(bson.M {})。All(& data)
// handle err
for _,doc: =范围数据{
for key,value:= range doc {
fmt.Println(key,value)
}
}
I am working with mgo
to use MongoDB with Go. I have the following code:
func Find(collectionName, dbName string, query interface{}) (result []interface{}, err error) {
collection := session.DB(dbName).C(collectionName)
err = collection.Find(query).All(&result)
return result, err
}
func GetTransactionID() (id interface{}, err error) {
query := bson.M{}
transId, err := Find("transactionId", dbName, query)
for key, value := range transId {
fmt.Println("k:", key, "v:", value)
}
}
Output:
k: 0 v: map[_id:ObjectIdHex("536887c199b6d0510964c35b") transId:A000000000]
I need to get the values of _id
and transId
from the map value returned in the slice from Find
. How can I do that?
I'm just guessing but in case you just want to retrieve all Transaction documents and print them - here is how:
Given you have a struct
representing the structure of the documents of your collection e.g.:
type Transaction struct {
Id bson.ObjectId `bson:"_id"`
TransactionId string `bson:"transId"`
}
You can obtain all the documents using the MongoDB driver (mgo):
var transactions []Transaction
err = c.Find(bson.M{}).All(&transactions)
// handle err
for index, transaction := range transactions {
fmt.Printf("%d: %+v\n", index, transaction)
}
Addition (generic solution)
OK, after you provided some more insight this might be a generic solution without using a struct. Try to marshall into a BSON document bson.M
(not tested):
var data []bson.M
err := c.Find(bson.M{}).All(&data)
// handle err
for _, doc := range data {
for key, value := range doc {
fmt.Println(key, value)
}
}
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