🔃 github.com/elliotchance/orderedmap/v2
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/v2"
func main() {
m := orderedmap.NewOrderedMap[string, any]()
m.Set("foo", "bar")
m.Set("qux", 1.23)
m.Set("123", true)
m.Delete("qux")
}
Note: 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 combined with a
trimmed down linked list to maintain the order.
Iterating
Be careful using Keys()
as it will create a copy of all of the keys so it's
only suitable for a small number of items:
for _, key := range m.Keys() {
value, _:= m.Get(key)
fmt.Println(key, value)
}
For larger maps you should use Front()
or Back()
to iterate per element:
// 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)
}
The iterator is 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.