插入地图作为golang中的地图字段

Question

I am trying to create a struct, one of whose fields is a map. However, I cannot initialize it with a method and then insert a value with another method. It reports error

panic: assignment to entry in nil map

Coming from a Python background, I am confused on what I missed.

Here is the goal playground snippet

package main

type profile map[string]float64

type foobar struct {
    foo profile
    bar map[string]profile
}

func (fb foobar) Init() {
    fb.foo = make(profile)
    fb.bar = make(map[string]profile)
}

func (fb foobar) Set() {
    fb.bar["foo1"] = make(profile)
}

func main() {
    test := foobar{}
    test.Init()
    test.Set()
}

Answer 1

The Init method receiver (fb foobar) is a value. It should be a pointer (fb *foobar). For example,

package main

type profile map[string]float64

type foobar struct {
    foo profile
    bar map[string]profile
}

func (fb *foobar) Init() {
    fb.foo = make(profile)
    fb.bar = make(map[string]profile)
}

func (fb foobar) Set() {
    fb.bar["foo1"] = make(profile)
}

func main() {
    test := foobar{}
    test.Init()
    test.Set()
}

Reference:

Should I define methods on values or pointers?