ordered-map

Package orderedmap defines a generic Ordered Map data structure with an API similar to that of container/list.

The intent of an ordered map is to retain a map's key insertion order, similar to LinkedHashMap from Java. It is not to constrain a map to sorted order.

Usage

Go does not allow for extensions to built-in maps. As such there is no "range" or keyed assignments.

Construct a map with contents as follows:

myMap := orderedmap.New[string, string].
    Set("First", "1st").
    Set("Second", "2nd").
    Set("Third", "3rd")

Iterate the map with the provided iterator:

it := myMap.Iterator()
for i := it.Next(); i != nil; i = it.Next() {
    fmt.Printf("Shorthand for %q is %q.\n", i.Key, i.Value)
}

Or, with lengthier for loops:

it := myMap.Iterator()
var i *orderedmap.KeyValuePair[string, string]
for {
    i = it.Next()
    if i == nil {
        break
    }
    fmt.Printf("Shorthand for %q is %q.\n", i.Key, i.Value)
}

Get the value defined at some key:

myValue, ok := myMap.Get("Second")

There are also some utility functions:

myValue:= myMap.GetOrDefault("Tenth", "10th")
first := myMap.First()
last := myMap.Last()

There are functions to manipulate the map as well (including the order of elements):

removed, ok := myMap.Remove("First")
err := myMap.MoveToFront("Third")
err := myMap.MoveToBack("Third")
err := myMap.MoveAfter("Third", "Second")
err := myMap.MoveBefore("Third", "Fourth")
err := myMap.InsertAfter("Third", "3rd", "Second")
err := myMap.InsertBefore("Third", "3rd", "Fourth")

Install

go get -u github.com/jimschubert/ordered-map

License

This project is licensed under Apache 2.0.