Lest Frequently Used (LFU) Cache

This is an in memory implementation of a least frequently used (LFU) cache in Go with constant time complexity O(1) for Set, Set, and Cache Eviction operations. The least recently used item is evicted in the case where 2 items thems have the same least frequency.

It's based on this paper http://dhruvbird.com/lfu.pdf by some very smart people

Documentation

You can use view the standard documentation on https://pkg.go.dev/github.com/NdoleStudio/lfu-cache. I wrote a beginner friendly blog post here

Install

go get https://github.com/NdoleStudio/lfu-cache/v2

Usage

• To get started, import the lfu-cache package and create a cache instance. New() returns an ErrInvalidCap error if you input a capacity which is less than or equal to 0.

  import"https://github.com/NdoleStudio/lfu-cache/v2"// creating the cache with capacity 3cache, err:= lfucache.New[string, int](3)
  iferr!=nil {
  // the cap is invalid
  }
  // DO NOT DO THIScache:= lfucache.Cache{}

• Inserting a value in the cache. Set() returns ErrInvalidCap if the cache capacity is less than or equal to zero. Ideally you should NEVER get this error

  err:=cache.Set("key", "value")
  iferr!=nil {
  // the cap is invalid
  }

• Getting a value in from the cache. Get() returns ErrCacheMiss if there is a cache miss

  val, err:=cache.Get("key")
  iferr!=nil {
  // cache miss
  }
  oriferr==lfucache.ErrCacheMiss { // cache miss
  }
  println(val) // val is of type `int`

• There are some helper methods like IsEmpty(), Len(), IsFullCap()

  // creating the cache with capacity 3cache, _:= lfucache.New[string, string](3)
  // setting a value_=cache.Set("key", "value")
  cache.IsEmpty() // returns falsecache.Len() // returns 1 because there is 1 item in the cachecache.IsFull() // returns false because the cache is not fullcache.Cap() // returns 3 which is the capacity of the cache

Running Tests

To run tests, cd to the project directory and run

go test -v 

Versioning

We use SemVer for versioning. For the versions available, see the tags on this repository.

Authors

• AchoArnold

See also the list of contributors who participated in this project.

License

This project is licensed under the MIT License - see the LICENSE file for details