Go lang map multi result

var newR[] struct {
		id string
		eventid string
		excel_id string
		userid string
		hallid string
}

i := 0
for rows.Next() {
    var id, eventid, excel_id, userid, hallid string
    err = rows.Scan(&id, &eventid, &excel_id, &userid, &hallid)
    
    // Here is what I want to do
    newR[i].id = id
	newR[i].eventid = eventid
	newR[i].excel_id = excel_id
	newR[i].userid = userid
	newR[i].hallid = hallid
    i++
}

Eventually I got an error msg "runtime error: index out of range"
In /myapp/app/controllers/app.go (around line 122)

newR[i].id = id

Any suggestions or tips will helps. Thanks.

Use append to add a new element and initialize a not yet allocated slice.

newElement := struct {
    id string
    eventid string
    excel_id string
    userid string
    hallid string
} {
    id: id,
    eventid: eventid,
    excel_id: excel_id,
    userid: userid,
    hallid: hallid,
}
newR = append(newR, newElement)

...

Sorry for not fmt or test it out but I typed this from my mobile.

You do not need to create a local variables for each field, just create a struct and use it to read data into and use a slice to accumulate results:

// struct definition must be out of functions body
type newR struct {
    id string
    eventid string
    excel_id string
    userid string
    hallid string
}

var newRs []newR
for rows.Next() {
    var current newR
    err = rows.Scan(&current.id, &current.eventid, &current.excel_id, &current.userid, &current.hallid)
    newRs = append(newRs, r)
}

And also it is better to check for errors after rows.Next() and rows.Scan(...).