英文:
How to delete Nth element in MongoDB array with golang?
问题
我需要删除expenses中的第一个或第二个元素。
{"_id": {"$oid": "12"},"chatID": {"$numberInt": "12"},"expenses": [{"category": "food", "amount": {"$numberDouble": "12.0"}},{"category": "food", "amount": {"$numberDouble": "14.0"}}],"income": []}
类似于 expenses[0].Delete()。
结果应该是这样的：
{"_id": {"$oid": "12"},"chatID": {"$numberInt": "12"},"expenses": [{"category": "food", "amount": {"$numberDouble": "14.0"}}],"income": []}
英文:
I need to delete first or second element in expenses
{"_id":{"$oid":"12"},"chatID":{"$numberInt":"12"},"expenses":[{"category":"food","amount":{"$numberDouble":"12.0"}},{"category":"food","amount":{"$numberDouble":"14.0"}}],"income":[]}
Smth like expenses[0].Delete()
Result should be like this:
{"_id":{"$oid":"12"},"chatID":{"$numberInt":"12"},"expenses":[{"category":"food","amount":{"$numberDouble":"14.0"}}],"income":[]}
答案1
得分: 1
你需要使用$unset更新命令，并手动提及数组键名以及其索引。
更新命令：
_, err = collection.UpdateOne(ctx,bson.D{}, // <- 查找参数bson.D{{"$unset", bson.D{{"expenses."+indexToRemove, 1}, // <- 从`expenses`数组中删除第`indexToRemove`个元素}},},)
完整的Go代码：
package mainimport ("context""fmt""go.mongodb.org/mongo-driver/bson""go.mongodb.org/mongo-driver/mongo""go.mongodb.org/mongo-driver/mongo/options""time")func main() {ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)defer cancel()mClient, err := mongo.Connect(ctx, options.Client().ApplyURI("mongodb://localhost:27017"))defer func() {if err = mClient.Disconnect(ctx); err != nil {panic(err)}}()collection := mClient.Database("temp").Collection("tmp10")ctx, cancel = context.WithTimeout(context.Background(), 5*time.Second)defer cancel()var result bson.Merr = collection.FindOne(ctx, bson.D{}).Decode(&result)fmt.Println(result)indexToRemove := "0" // <- 输入要删除的索引，可以是字符串或将其转换为字符串_, err = collection.UpdateOne(ctx,bson.D{},bson.D{{"$unset", bson.D{{"expenses."+indexToRemove, 1}, // <- 从`expenses`数组中删除第`indexToRemove`个元素}},},)if err != nil {fmt.Println(err)}err = collection.FindOne(ctx, bson.D{}).Decode(&result)fmt.Println(result)}
英文:
You have to make use of the $unset update command and manually mention the array key name along with its index.
Update Command:
_, err = collection.UpdateOne(ctx,bson.D{}, // <- Find Parameterbson.D{{"$unset", bson.D{{"expenses."+indexToRemove, 1}, // <- Removes `indexToRemove` th element from `expenses` array}},},)
Full Go Code
package mainimport ("context""fmt""go.mongodb.org/mongo-driver/bson""go.mongodb.org/mongo-driver/mongo""go.mongodb.org/mongo-driver/mongo/options""time")func main() {ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)defer cancel()mClient, err := mongo.Connect(ctx, options.Client().ApplyURI("mongodb://localhost:27017"))defer func() {if err = mClient.Disconnect(ctx); err != nil {panic(err)}}()collection := mClient.Database("temp").Collection("tmp10")ctx, cancel = context.WithTimeout(context.Background(), 5*time.Second)defer cancel()var result bson.Merr = collection.FindOne(ctx, bson.D{}).Decode(&result)fmt.Println(result)indexToRemove := "0" // <- Input index to remove in string or convert it into string_, err = collection.UpdateOne(ctx,bson.D{},bson.D{{"$unset", bson.D{{"expenses."+indexToRemove, 1}, // <- Removes `indexToRemove` th element from `expenses` array}},},)if err != nil {fmt.Println(err)}err = collection.FindOne(ctx, bson.D{}).Decode(&result)fmt.Println(result)}
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