Files
extypes/set.go

161 lines
3.5 KiB
Go

package extypes
import (
"fmt"
"reflect"
"strings"
)
// Set is a uniqueness-enforcing collection backed by a slice.
//
// Order is preserved based on first appearance. Equality is order-sensitive
// because the underlying representation is a slice.
type Set[T any] []T
// NewSetFrom returns a new Set with duplicate values removed.
func NewSetFrom[T any](slice []T) Set[T] {
s := make(Set[T], 0)
for _, v := range slice {
if s.Index(v) >= 0 {
continue
}
s = append(s, v)
}
return s
}
// Len returns the number of elements in s.
func (s Set[T]) Len() int { return len(s) }
// Cap returns the capacity of s.
func (s Set[T]) Cap() int { return cap(s) }
// Get returns the element at index.
func (s Set[T]) Get(index int) T { return s[index] }
// Last returns the last element.
func (s Set[T]) Last() T { return s.Get(s.Len() - 1) }
// First returns the first element.
func (s Set[T]) First() T { return s.Get(0) }
// Index returns the first index of el or -1 when el is not present.
// Comparison uses reflect.DeepEqual.
func (s Set[T]) Index(el T) int {
for i := range s {
if reflect.DeepEqual(s[i], el) {
return i
}
}
return -1
}
// Swap swaps two elements in place.
func (s Set[T]) Swap(i, j int) {
s[i], s[j] = s[j], s[i]
}
// Add appends v if it is not already present.
func (s Set[T]) Add(v T) Set[T] {
index := s.Index(v)
if index >= 0 {
return s
}
return append(s, v)
}
// Pop removes the element at index and returns the resulting set.
func (s Set[T]) Pop(index int) Set[T] {
if index == 0 {
return s[1:]
}
out := make(Set[T], s.Len()-1)
copy(out, s[:index])
copy(out[index:], s[index+1:])
return out
}
// Remove removes the first matching element and returns the resulting set.
func (s Set[T]) Remove(el T) Set[T] {
index := s.Index(el)
if index == -1 {
return s
}
return s.Pop(index)
}
// Equal reports whether both sets have the same length and pairwise equal
// elements in the same order according to reflect.DeepEqual.
func (s Set[T]) Equal(s2 Set[T]) bool {
if s.Len() != s2.Len() {
return false
}
for i := range s {
if !reflect.DeepEqual(s[i], s2[i]) {
return false
}
}
return true
}
// ToSlice returns a copy of s as a Slice.
func (s Set[T]) ToSlice() Slice[T] { return NewSliceFrom(s) }
// ToTuple returns a Tuple view of s without copying.
func (s Set[T]) ToTuple() Tuple[T] { return NewTupleFrom(s) }
// ToArray returns a copy of s as a built-in slice.
func (s Set[T]) ToArray() []T {
out := make([]T, len(s))
copy(out, s)
return out
}
// ToAnyArray returns a copy of s converted to []any.
func (s Set[T]) ToAnyArray() []any {
out := make([]any, len(s))
for i, v := range s {
out[i] = v
}
return out
}
// Filter returns a new Set containing only elements accepted by f.
// The result preserves order and therefore remains duplicate-free.
func (s Set[T]) Filter(f func(e T) bool) Set[T] {
out := make(Set[T], 0)
for _, v := range s {
if f(v) {
out = append(out, v)
}
}
return out
}
// ForEach calls f for every element and returns s.
func (s Set[T]) ForEach(f func(int, T)) Set[T] {
for i, v := range s {
f(i, v)
}
return s
}
// Map applies f to each element in place and returns s.
// It does not remove duplicates that may be produced by f.
func (s Set[T]) Map(f func(e T) T) Set[T] {
for i, v := range s {
s[i] = f(v)
}
return s
}
// Join formats every element with fmt.Sprintf("%v", value) and joins them
// using sep.
func (s Set[T]) Join(sep string) string {
st := make([]string, len(s))
for i, v := range s {
st[i] = fmt.Sprintf("%v", v)
}
return strings.Join(st, sep)
}