golang在for循环中追加问题

Question

问题：append下面的内部Users()for 循环将users3x 中的最后一项添加到userRxs []*UserResolver期待：append应该将里面的每个项目添加users到userRxs []*UserResolver// Users return all users from Dbfunc (r *RootResolver) Users() ([]*UserResolver, error) {    var userRxs []*UserResolver    users := r.Db.Users()    for _, u := range users {        log.Printf("userID: %s, username: %s, email: %s, password: %s", u.UserID, u.Username, u.Email, u.Password)        userRxs = append(userRxs, &UserResolver{&u})    }    log.Printf("%v", userRxs)    return userRxs, nil}在 for 循环内，log.Printf打印这个userID: 0374402a-3dc4-48da-86c4-949905ccc26c, username: sunnysan, email: [e-mail], password: 12345678userID: 53f21c4f-2cd8-4e67-b3e9-5ef344806230, username: sunnysan2, email: [e-mail], password: 12345678userID: 0a47d3af-03dc-4050-a028-7a41599af497, username: sunnysan3, email: [e-mail], password: 12345678 在 for 循环之后，log.Printf("%v", userRxs)打印这个[  User {     userID: 0a47d3af-03dc-4050-a028-7a41599af497,     username: sunnysan3,     email: [e-mail],     password: 12345678   }  User {     userID: 0a47d3af-03dc-4050-a028-7a41599af497,     username: sunnysan3,     email: [e-mail],     password: 12345678   }  User {     userID: 0a47d3af-03dc-4050-a028-7a41599af497,     username: sunnysan3,     email: [e-mail],     password: 12345678   }]这是整个文件以获取更多上下文package mainimport (    "fmt"    "log"    graphql "github.com/graph-gophers/graphql-go")/* *  User GQL type        type User {        userID: ID!        username: String!        email: String!        password: String!    }*/// User type should match the exact shape of the schema commented abovetype User struct {    UserID   graphql.ID    Username string    Email    string    Password string}// RootResolver ingests Db to run queries (getters) against ittype RootResolver struct {    *Db}

Answer 1

范围变量在每次迭代时都会被覆盖，并且&u是相同的。所以你最终UserResolver会多次附加一个包含相同地址的地址。您需要使用该变量的本地副本。尝试这个：

for _, u := range users {

        u:=u  // Make a copy of the variable and redeclare it

        userRxs = append(userRxs, &UserResolver{&u})

    }