The highest tagged major version is
README
¶
🔃 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.
Documentation
¶
Index ¶
- type Element
- type OrderedMap
- func (m *OrderedMap) Back() *Element
- func (m *OrderedMap) Copy() *OrderedMap
- func (m *OrderedMap) Delete(key interface{}) (didDelete bool)
- func (m *OrderedMap) Front() *Element
- func (m *OrderedMap) Get(key interface{}) (interface{}, bool)
- func (m *OrderedMap) GetElement(key interface{}) *Element
- func (m *OrderedMap) GetOrDefault(key, defaultValue interface{}) interface{}
- func (m *OrderedMap) Keys() (keys []interface{})
- func (m *OrderedMap) Len() int
- func (m *OrderedMap) Set(key, value interface{}) bool
Examples ¶
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
This section is empty.
Types ¶
type Element ¶
type Element struct {
// The key that corresponds to this element in the ordered map.
Key interface{}
// The value stored with this element.
Value interface{}
// contains filtered or unexported fields
}
Element is an element of a null terminated (non circular) intrusive doubly linked list that contains the key of the correspondent element in the ordered map too.
type OrderedMap ¶
type OrderedMap struct {
// contains filtered or unexported fields
}
func NewOrderedMap ¶
func NewOrderedMap() *OrderedMap
Example ¶
package main
import (
"fmt"
"github.com/elliotchance/orderedmap"
)
func main() {
m := orderedmap.NewOrderedMap()
m.Set("foo", "bar")
m.Set("qux", 1.23)
m.Set(123, true)
m.Delete("qux")
for _, key := range m.Keys() {
value, _ := m.Get(key)
fmt.Println(key, value)
}
}
Output:
func (*OrderedMap) Back ¶
func (m *OrderedMap) Back() *Element
Back will return the element that is the last (most recent Set element). If there are no elements this will return nil.
func (*OrderedMap) Copy ¶ added in v1.4.0
func (m *OrderedMap) Copy() *OrderedMap
Copy returns a new OrderedMap with the same elements. Using Copy while there are concurrent writes may mangle the result.
func (*OrderedMap) Delete ¶
func (m *OrderedMap) Delete(key interface{}) (didDelete bool)
Delete will remove a key from the map. It will return true if the key was removed (the key did exist).
func (*OrderedMap) Front ¶
func (m *OrderedMap) Front() *Element
Front will return the element that is the first (oldest Set element). If there are no elements this will return nil.
Example ¶
package main
import (
"fmt"
"github.com/elliotchance/orderedmap"
)
func main() {
m := orderedmap.NewOrderedMap()
m.Set(1, true)
m.Set(2, true)
for el := m.Front(); el != nil; el = el.Next() {
fmt.Println(el)
}
}
Output:
func (*OrderedMap) Get ¶
func (m *OrderedMap) Get(key interface{}) (interface{}, bool)
Get returns the value for a key. If the key does not exist, the second return parameter will be false and the value will be nil.
func (*OrderedMap) GetElement ¶ added in v1.3.0
func (m *OrderedMap) GetElement(key interface{}) *Element
GetElement returns the element for a key. If the key does not exist, the pointer will be nil.
func (*OrderedMap) GetOrDefault ¶
func (m *OrderedMap) GetOrDefault(key, defaultValue interface{}) interface{}
GetOrDefault returns the value for a key. If the key does not exist, returns the default value instead.
func (*OrderedMap) Keys ¶
func (m *OrderedMap) Keys() (keys []interface{})
Keys returns all of the keys in the order they were inserted. If a key was replaced it will retain the same position. To ensure most recently set keys are always at the end you must always Delete before Set.
func (*OrderedMap) Len ¶
func (m *OrderedMap) Len() int
Len returns the number of elements in the map.
func (*OrderedMap) Set ¶
func (m *OrderedMap) Set(key, value interface{}) bool
Set will set (or replace) a value for a key. If the key was new, then true will be returned. The returned value will be false if the value was replaced (even if the value was the same).
Source Files