Golang：创建切片结构

Question

I want to create a list of structs that can be returned by a function in a manner as it is in the go-github package.

But what is the correct way to create and populate such a list?

I found two ways, e.g., using the append():

...
    allowedRepos := strings.Fields("repo1, repo2")

    actualRepos := []Repos{}
    actualRepos = append(actualRepos, Repos{Name: "repo1", URL: "gth.com/repo1"})
    actualRepos = append(actualRepos, Repos{Name: "repo2", URL: "gth.com/repo2"})
...

And by a "direct initialization:

...
    actualRepos := []Repos{
        Repos{Name: "repo1", URL: "gth.com/repo1"},
        Repos{Name: "repo2", URL: "gth.com/repo2"},
    }  

They works but both look bit awkward and wrong.

So - what is the best way to do it?

It looks like need to create it using pointer but can't make it work.

Answer 1

but both look bit awkward and wrong

Actually there is nothing wrong, both approaches are correct and valid.
The only difference - is slice population time.
In 2nd approach you're populating slice during development time, it means this code:

actualRepos := []Repos{
    Repos{Name: "repo1", URL: "gth.com/repo1"},
    Repos{Name: "repo2", URL: "gth.com/repo2"},
} 

always will create slice with 2 elements in it.

But wit 1st approach you can populate slice in runtime using append(), like:

actualRepos := []Repos{}
for _, repo := range allRepos {
  actualRepos = append(actualRepos, repo)
}

so now all depends on allRepos and now this code have dynamic behaviour which is determined in runtime.

It looks like need to create it using pointer

Please pay attention that slice itself passes by reference, for example:

s := [...]string{"r", "o", "a", "d"}
s2 := s[:]
s[3] = "x"

Result will be:

// s = [r o a x], s2 = [r o a x]