Documentation
¶
Overview ¶
Package mapset implements a basic set type using a built-in map.
The Set type is a thin wrapper on a built-in Go map, so a Set is not safe for concurrent use without external synchronization.
Example ¶
package main
import (
"fmt"
"strings"
"github.com/creachadair/mds/mapset"
)
func main() {
s := mapset.New(strings.Fields("a man a plan")...)
// Add individual elements.
s.Add("panama", "canal")
// Add the contents of another set.
t := mapset.New("plan", "for", "the", "future")
s.AddAll(t)
// Remove items and convert to a slice.
elts := s.Remove("a", "an", "the", "for").Slice()
// Clone and make other changes.
u := s.Clone().Remove("future", "plans")
// Do some basic comparisons.
fmt.Println("t intersects u:", t.Intersects(u))
fmt.Println("t equals u:", t.Equals(u))
fmt.Println()
// The slice is unordered, so impose some discipline.
fmt.Println(strings.Join(elts, "\n"))
}
Output: t intersects u: true t equals u: false canal future man panama plan
Index ¶
- type Set
- func (s *Set[T]) Add(items ...T) Set[T]
- func (s *Set[T]) AddAll(t Set[T]) Set[T]
- func (s Set[T]) Append(vs []T) []T
- func (s Set[T]) Clear() Set[T]
- func (s Set[T]) Clone() Set[T]
- func (s Set[T]) Equals(t Set[T]) bool
- func (s Set[T]) Has(t T) bool
- func (s Set[T]) HasAll(ts ...T) bool
- func (s Set[T]) HasAny(ts ...T) bool
- func (s Set[T]) Intersects(t Set[T]) bool
- func (s Set[T]) IsEmpty() bool
- func (s Set[T]) IsSubset(t Set[T]) bool
- func (s Set[T]) Len() int
- func (s Set[T]) Pop() T
- func (s Set[T]) Remove(items ...T) Set[T]
- func (s Set[T]) RemoveAll(t Set[T]) Set[T]
- func (s Set[T]) Slice() []T
Examples ¶
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
This section is empty.
Types ¶
type Set ¶
type Set[T comparable] map[T]struct{}
A Set represents a set of distinct values. It is implemented via the built-in map type, and the underlying map can also be used directly to add and remove items and to iterate the contents.
func Intersect ¶
func Intersect[T comparable](ss ...Set[T]) Set[T]
Intersect constructs a new set containing the intersection of the specified sets. The result is never nil, even if the given sets are empty.
func Keys ¶ added in v0.2.3
func Keys[T comparable, U any](m map[T]U) Set[T]
Keys constructs a new Set containing the keys of m. The result is never nil, even if m is empty.
Example ¶
package main
import (
"fmt"
"strings"
"github.com/creachadair/mds/mapset"
)
func main() {
s := mapset.Keys(map[string]int{
"apple": 1,
"pear": 2,
"plum": 3,
"cherry": 4,
})
fmt.Println(strings.Join(s.Slice(), "\n"))
}
Output: apple cherry pear plum
func New ¶
func New[T comparable](items ...T) Set[T]
New constructs a set of the specified items. The result is never nil, even if no items are provided.
func NewSize ¶
func NewSize[T comparable](n int) Set[T]
NewSize constructs a new empty set preallocated to have space for n items.
func Values ¶ added in v0.2.3
func Values[T, U comparable](m map[T]U) Set[U]
Values constructs a new Set containing the values of m. The result is never nil, even if m is empty.
Example ¶
package main
import (
"fmt"
"github.com/creachadair/mds/mapset"
)
func main() {
s := mapset.Values(map[string]int{
"apple": 5,
"pear": 4,
"plum": 4,
"cherry": 6,
})
for _, v := range s.Slice() {
fmt.Println(v)
}
}
Output: 4 5 6
func (Set[T]) Append ¶ added in v0.14.2
func (s Set[T]) Append(vs []T) []T
Append appends the elements of s to the specified slice in arbitrary order, and returns the resulting slice. If cap(vs) ≥ len(s) this will not allocate.
func (Set[T]) Clone ¶
Clone returns a new set with the same contents as s. The value returned is never nil.
func (Set[T]) HasAll ¶ added in v0.1.0
HasAll reports whether s contains all the elements of ts. It is semantically equivalent to ts.IsSubset(s), but does not construct an intermediate set. It returns true if len(ts) == 0.
func (Set[T]) HasAny ¶
HasAny reports whether s contains any element of ts. It is semantically equivalent to ts.Intersects(s), but does not construct an intermediate set. It returns false if len(ts) == 0.
func (Set[T]) Intersects ¶
Intersects reports whether s and t share any elements in common.
func (Set[T]) Pop ¶
func (s Set[T]) Pop() T
Pop removes and returns an arbitrary element of s, if s is non-empty. If s is empty, it returns a zero value.
Source Files