🔃 github.com/elliotchance/orderedmap

Installation

go get -u github.com/elliotchance/orderedmap

Basic Usage

An *OrderedMap is a high performance ordered map that maintains amortized O(1) for Set, Get, Delete and Len:

m := orderedmap.NewOrderedMap()

m.Set("foo", "bar")
m.Set("qux", 1.23)
m.Set(123, true)

m.Delete("qux")

Internally an *OrderedMap uses a combination of a map and linked list.

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.

Performance

CPU: Intel(R) Core(TM) i5-8250U CPU @ 1.60GHz

RAM: 8GB

System: Windows 10

$go test -benchmem -run=^$ github.com/elliotchance/orderedmap -bench BenchmarkAll

map[int]bool

map[string]bool(PS : Use strconv.Itoa())

Big map[int]bool (10000000 keys)

Big map[string]bool (10000000 keys)