无法将复合文字与map [string] [] struct一起使用[关闭]

Question

I am trying to use composite literal with maps but unable to use it as it shows some error.

please find the code below.

I am a newbie to Golang and perhaps have some less understanding about composite literals.

type Assessment struct{
    StructuringForce map[string][]StructuringForce
}

type StructuringForce struct {
    Principles       map[string][]Capabilities
}

type Capability struct {
}

c1 := Capability{}

a1 := Assessment{

        StructuringForce : map[string][]StructuringForce{
            "Information Systems" , []StructuringForce{
                StructuringForce{
                    Principles : map[string][]Capabilities{
                        "Integration of IT Services" ,[]Capabilities{
                            c1,
                        },
                    },
                },
            },
        },


    }

while constructing "a1" with composite literals I get "Missing key in map literals error".

But i can see that i have added keys.

Answer 1

As Volker pointed out, make cannot be used with literals. In your case it can either be:

make(map[string][]StructuringForce)

or

map[string][]StructuringForce{}{}

Secondly, for golang map, it's using : to separate the key-value, so it should be like:

a := map[string]string{
  "foo": "bar",
}

Thirdly, you don't have Capabilities defined, so I suppose you're trying to do Capability.

To sum up, the entire thing in the main func should look like:

c1 := Capability{}

a1 := Assessment{
        StructuringForce: map[string][]StructuringForce{
            "Information Systems": []StructuringForce{
                StructuringForce{
                    Principles: map[string][]Capability{
                        "Integration of IT Services": []Capabilities{
                            c1, // missing comma here as well
                        },
                    },
                },
            },
        },
    }

However, based on what you pasted, I would suggest you start from something straightforward to get started with the syntax and how to compose a map, like Go By Examples.

Another suggestion is that you can wrap the running code in main func when posting a SO question, which will make reproducing the issue a lot easier and more understandable to others who try to help.