一种将一种类型的切片转换为等效类型的切片的优雅方法？

Question

A motivating example:

Implementing various scheduling "strategies", which sort a list of Jobs.

type Job struct {
    weight int
    length int
}

// Given a slice of Jobs, re-order them.
type Strategy func([]Job) []Job

func Schedule(jobs []Job, strat Strategy) []Job {
    return strat(jobs)
}

One very simple strategy is to execute the shortest jobs first (disregarding their weight/priority).

func MinCompletionTimes(job []Job) []Job {
    // Hmm...   
}

Well, this strategy is nothing more than a sort on job.length, so let's use the sort package. Define a custom type, and implement sort.Interface...

type JobSlice []Job // Should probably be called MinCompletionTimesJobSlice

func (js JobSlice) Len() {
    return len(js)
}

func (js JobSlice) Less(i, j int) bool {
    return js[i].length < js[j].length
}

func (js JobSlice) Swap(i, j int) {
    js[i], js[j] = js[j], js[i]
}

Hooray, now to back to our simple strategy...

func MinCompletionTimes(jobs []Job) []Job {
    sort.Sort([]JobSlice(jobs)) // cannot convert jobs (type []Job) to type []JobSlice
    return jobs
}

Er...

Answer 1

First of all, I don't see Jobs defined anywhere even though you use it like jobs []Jobs.

I think you mean Job since the error states cannot convert jobs (type []Job), so I'll assume that when you're doing []Jobs, you really mean []Job.

---

If so, then with this, y You're trying to convert a slice of Job to a slice of JobSlice, the which has an underlying type of []Job.

[]JobSlice(jobs) // converting a slice of Job to a slice of slices of Job?

In other words, you're trying to convert []Job to effectively [][]Job. Instead I think you just wanted to convert your []Job to JobSlice

JobSlice(jobs)

---

So taking out a bunch of the code, you can see that this conversion will work.

type Job struct {
    weight int
    length int
}

type JobSlice []Job

func main() {
    x := []Job{{},{}}

    y := JobSlice(x)
    z := []Job(y)

    fmt.Println(x, y, z)
}