Sorting by slice fields

Question

I have the following Structs:

type Parent struct {
    id       string
    children []Child
}

type Child struct {
    id string
}

I have made a slice of Parents with the following values:

parents := make([]Parent, 0)

p1 := Parent {
    "3",
    []Child {
        {"2"},
        {"3"},
        {"1"},
    },
}

p2 := Parent {
    "1",
    []Child {
        {"8"},
        {"9"},
        {"7"},
    },
}

p3 := Parent {
    "2",
    []Child {
        {"5"},
        {"6"},
        {"4"},
    },
}             

parents = append(parents, p1, p2, p3)

I am trying to sort the "parents" slice in the following order:

1) First, sort all Parents by Parent.id

2) Next, sort each Parent's "children" slice by Child.id

The expected result is something like:

[{1 [{7} {8} {9}]} {2 [{4} {5} {6}]} {3 [{1} {2} {3}]}]

Is there a way to do this in Go?

Answer 1

I got it to work using the following code:

// sort each Parent in the parents slice by Id
sort.Slice(parents, func(i, j int) bool {return parents[i].id < parents[j].id})

// for each Parent, sort each Child in the children slice by Id
for _, parent := range parents {
    sort.Slice(parent.children, func(i, j int) bool {return parent.children[i].id < parent.children[j].id})
}

Special thanks to @Volker for mentioning the sort.Slice function! I had no idea it existed!