是否可以在没有两个索引调用的情况下更新和检索Map中的元素？

I have a map with integer values. I want to update a value and then check if the updated value exceeds a threshold.

If I didn't need to check the new value, then I would simply do

map[key] += 1

The obvious change if I want to check the new value would be:

old_val := map[key]
new_val := old_val + 1
map[key] = new_val
if (new_val > threshold) {
    return
}

However, this makes two index calls to the map, which is not necessarily a constant time operation.

What I would like to do is something like:

val_p := &(map[key])
*(val_p) += 1
if (*(val_p) > threshold) {
    return
}

However, GoLang maps are not addressable by design because the addresses can obviously change (although it wouldn't change in this case because I'm not altering the map).

Is there some function I could use to update the element in a map which returns the new value? Specifically for integers?

You can't do it with "simple" values for the reasons you mentioned in the question.

What you may do is store a wrapper or a pointer in the map, and so you only need to lookup the value, and you only need to do it once; changing the data is changing the pointed value which is outside of the map, so you don't have to reassign (the pointer doesn't change).

For example:

const threshold = 3

m := map[string]*int{
    "one": new(int),
}

for {
    p := m["one"]
    fmt.Println("data=", *p)
    *p++
    if *p > threshold {
        fmt.Println("threshold reached", *p)
        break
    }
}

This outputs (try it on the Go Playground):

data= 0
data= 1
data= 2
data= 3
threshold reached 4

Although note that this may not be faster due to pointer indirections. Measure if this is a critical part of your app.