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package set
import (
"sort"
"strings"
)
// Set implements basic string set operations.
type Set map[string]struct{}
// Add adds an element.
func (s *Set) Add(v string) *Set {
(*s)[v] = struct{}{}
return s
}
// Len returns number of elements in set.
func (s *Set) Len() int {
return len(*s)
}
// IsEmpty returns if set has zero elements.
func (s *Set) IsEmpty() bool {
return s.Len() == 0
}
// Equals returns true, if sets contain the same elements.
func (s *Set) Equals(t *Set) bool {
for k := range *s {
if !t.Contains(k) {
return false
}
}
return s.Len() == t.Len()
}
// Contains returns membership status.
func (s *Set) Contains(v string) bool {
_, ok := (*s)[v]
return ok
}
// Intersection returns a new set containing all elements found in both sets.
func (s *Set) Intersection(t *Set) *Set {
u := New()
for _, v := range s.Slice() {
if t.Contains(v) {
u.Add(v)
}
}
return u
}
// Union returns the union of two sets.
func (s *Set) Union(t *Set) *Set {
u := New()
for _, v := range s.Slice() {
u.Add(v)
}
for _, v := range t.Slice() {
u.Add(v)
}
return u
}
// Slice returns all elements as a slice.
func (s *Set) Slice() (result []string) {
for k := range *s {
result = append(result, k)
}
return
}
// SortedSlice returns all elements as a slice, sorted.
func (s *Set) SortedSlice() (result []string) {
for k := range *s {
result = append(result, k)
}
sort.Strings(result)
return
}
// TopK returns at most k elements.
func (s *Set) TopK(k int) *Set {
var top []string
for i, v := range s.SortedSlice() {
if i < k {
top = append(top, v)
}
}
return FromSlice(top)
}
func (s *Set) Product(t *Set) (result [][]string) {
for k := range *s {
for l := range *t {
result = append(result, []string{k, l})
}
}
return
}
// Jaccard returns the jaccard index of sets s and t.
func (s *Set) Jaccard(t *Set) float64 {
if s.IsEmpty() && t.IsEmpty() {
return 1
}
if u := s.Union(t); u.IsEmpty() {
return 0
} else {
return float64(s.Intersection(t).Len()) / float64(u.Len())
}
}
func (s *Set) Join(sep string) string {
return strings.Join(s.Slice(), sep)
}
// Max returns the size of the largest set.
func Max(ss ...*Set) (max int) {
for _, s := range ss {
if s.Len() > max {
max = s.Len()
}
}
return
}
// Min returns the size of the smallest set.
func Min(ss ...*Set) (min int) {
min = 2 << 30
for _, s := range ss {
if s.Len() < min {
min = s.Len()
}
}
return
}
func Filter(s *Set, f func(string) bool) *Set {
t := New()
for v := range *s {
if f(v) {
t.Add(v)
}
}
return t
}
// New creates a new set.
func New() *Set {
s := make(Set)
return &s
}
// FromSlice initializes a set from a slice.
func FromSlice(vs []string) *Set {
s := New()
for _, v := range vs {
s.Add(v)
}
return s
}
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