[英]How to retrieve value from map - go lang?
I am working with mgo
to use MongoDB with Go. 我正在使用
mgo
将MongoDB与Go一起使用。 I have the following code: 我有以下代码:
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] 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
. 我需要从
Find
的切片中返回的map值中获取_id
和transId
的值。 How can I do that? 我怎样才能做到这一点?
I'm just guessing but in case you just want to retrieve all Transaction documents and print them - here is how: 我只是猜测,但万一你想要检索所有交易文件并打印它们 - 这是如何:
Given you have a struct
representing the structure of the documents of your collection eg: 假设您有一个表示集合文档
struct
的结构,例如:
type Transaction struct {
Id bson.ObjectId `bson:"_id"`
TransactionId string `bson:"transId"`
}
You can obtain all the documents using the MongoDB driver (mgo): 您可以使用MongoDB驱动程序(mgo)获取所有文档:
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) 加法(通用解决方案)
OK, after you provided some more insight this might be a generic solution without using a struct. 好的,在您提供了更多的见解后,这可能是一个通用的解决方案而不使用结构。 Try to marshall into a BSON document
bson.M
(not tested): 尝试编组到BSON文档
bson.M
(未测试):
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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