https://github.com/elliotchance/orderedmap

🔃 An ordered map in Go with amortized O(1) for Set, Get, Delete and Len.
https://github.com/elliotchance/orderedmap

data-structures golang maps orderedmap

Last synced: 20 days ago
JSON representation

🔃 An ordered map in Go with amortized O(1) for Set, Get, Delete and Len.

• Host: GitHub
• URL: https://github.com/elliotchance/orderedmap
• Owner: elliotchance
• License: mit
• Created: 2019-11-14T21:12:26.000Z (almost 5 years ago)
• Default Branch: master
• Last Pushed: 2024-09-13T23:19:49.000Z (about 2 months ago)
• Last Synced: 2024-10-09T11:36:07.386Z (about 1 month ago)
• Topics: data-structures, golang, maps, orderedmap
• Language: Go
• Homepage:
• Size: 39.1 KB
• Stars: 832
• Watchers: 14
• Forks: 63
• Open Issues: 13
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

Awesome Lists containing this project

• go-awesome - orderedmap - ordered dictionary (Open source library / Data Structure)

README

        
# 🔃 github.com/elliotchance/orderedmap/v2 [![GoDoc](https://godoc.org/github.com/elliotchance/orderedmap/v2?status.svg)](https://godoc.org/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`:

```go

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](https://go.dev/blog/maps) 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:

```go

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:

```go

// 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)

}

```

In case you're using Go 1.23, you can also [iterate with

`range`](https://go.dev/doc/go1.23#iterators) by using `Iterator()` or

`ReverseIterator()` methods:

```go

for key, value := range m.Iterator() {

    fmt.Println(key, value)

}

for key, value := range m.ReverseIterator() {

    fmt.Println(key, 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.