Sometimes you’ll want to sort a collection by something other than its natural order. For example, sorting strings by their length instead of alphabetically.
Custom String Sorting
Implement a comparison function for custom sorting. cmp.Compare is helpful for this:
fruits := []string{"peach", "banana", "kiwi"}
// Comparison function for string lengths
lenCmp := func(a, b string) int {
return cmp.Compare(len(a), len(b))
}
// Sort using custom comparison
slices.SortFunc(fruits, lenCmp)
fmt.Println(fruits)
// Output: [kiwi peach banana]
Sorting Custom Types
Use the same technique to sort slices of values that aren’t built-in types:
type Person struct {
name string
age int
}
people := []Person{
Person{name: "Jax", age: 37},
Person{name: "TJ", age: 25},
Person{name: "Alex", age: 72},
}
// Sort people by age
slices.SortFunc(people,
func(a, b Person) int {
return cmp.Compare(a.age, b.age)
})
fmt.Println(people)
// Output: [{TJ 25} {Jax 37} {Alex 72}]
If the struct is large, consider using *Person instead and adjust the sorting function accordingly. If in doubt, benchmark! Key Functions
slices.SortFunc
func[S ~[]E, E any](x S, cmp func(a, b E) int)
Sorts a slice using a custom comparison function
cmp.Compare
func[T Ordered](x, y T) int
Returns -1 if x < y, 0 if x == y, +1 if x > y
Package Reference