Package: wnpp
Severity: wishlist
Owner: Christoph Martin <[email protected]>
* Package name : golang-github-elliotchance-orderedmap
Version : 1.8.0-1
Upstream Author : Elliot Chance
* URL : https://github.com/elliotchance/orderedmap
* License : Expat
Programming Lang: Go
Description : An ordered map in Go with amortized O(1) for Set,
Get, Delete and Len.
Basic Usage
.
An *OrderedMap is a high performance ordered map that maintains
amortized O(1) for Set, Get, Delete and Len:
.
import "github.com/elliotchance/orderedmap/v3"
.
func main() {
m := orderedmap.NewOrderedMap[string, any]()
.
m.Set("foo", "bar")
m.Set("qux", 1.23)
m.Set("123", true)
.
m.Delete("qux")
}
.
| [!NOTE]
|
| * *v3 requires Go v1.23* - If you need to support Go 1.18-1.22, you
can
| use v2.
| * *v2 requires Go v1.18 for generics* - If you need to support Go 1.
17
| or below, you can use v1.
.
Internally an *OrderedMap uses the composite type map
(https://go.dev/blog/maps) combined with a trimmed down linked list to
maintain the order.
.
Iterating
.
The following methods all return iterators
(https://go.dev/doc/go1.23#iterators) that can be used to loop over
elements in an ordered map:
.
* AllFromFront()
* AllFromBack()
* Keys()
* Values()
.
// Iterate through all elements from oldest to newest:
for key, value := range m.AllFromFront() {
fmt.Println(key, value)
}
.
Iterators are safe to use bidirectionally, and will return nil once it
goes beyond the first or last item. If the map is changing while the
iteration is in-flight it may produce unexpected behavior.
.
If you want to get a slice of the map keys or values, you can use the
standard slices.Collect method with the iterator returned from Keys() or
Values():
.
fmt.Println(slices.Collect(m.Keys())
// [A B C]
.
Likewise, calling maps.Collect on the iterator returned from
AllFromFront() will create a regular unordered map from the ordered one:
.
fmt.Println(maps.Collect(m.AllFromFront())
// [A:1 B:2 C:3]
.
If you don't want to use iterators, you can also manually loop over the
elements using Front() or Back() with Next():
.
// Iterate through all elements from oldest to newest:
for el := m.Front(); el != nil; el = el.Next() {
fmt.Println(el.Key, el.Value)
}
.
// You can also use Back and Prev to iterate in reverse:
for el := m.Back(); el != nil; el = el.Prev() {
fmt.Println(el.Key, el.Value)
}
