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golang-set

The missing generic set collection for the Go language. Until Go has sets built-in...use this.

Psst

Update 3/5/2023

With Generics

Coming from Python one of the things I miss is the superbly wonderful set collection. This is my attempt to mimic the primary features of the set collection from Python. You can of course argue that there is no need for a set in Go, otherwise the creators would have added one to the standard library. To those I say simply ignore this repository and carry-on and to the rest that find this useful please contribute in helping me make it better by contributing with suggestions or PRs.

Install

Use go get to install this package.

go get github.com/deckarep/golang-set/v2

Features

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Usage

The code below demonstrates how a Set collection can better manage data and actually minimize boilerplate and needless loops in code. This package now fully supports generic syntax so you are now able to instantiate a collection for any comparable type object.

What is considered comparable in Go?

Using this library is as simple as creating either a threadsafe or non-threadsafe set and providing a comparable type for instantiation of the collection.

// Syntax example, doesn't compile.
mySet := mapset.NewSet[T]() // where T is some concrete comparable type.

// Therefore this code creates an int set
mySet := mapset.NewSet[int]()

// Or perhaps you want a string set
mySet := mapset.NewSet[string]()

type myStruct struct {
  name string
  age uint8
}

// Alternatively a set of structs
mySet := mapset.NewSet[myStruct]()

// Lastly a set that can hold anything using the any or empty interface keyword: interface{}. This is effectively removes type safety.
mySet := mapset.NewSet[any]()

Comprehensive Example

package main

import (
  "fmt"
  mapset "github.com/deckarep/golang-set/v2"
)

func main() {
  // Create a string-based set of required classes.
  required := mapset.NewSet[string]()
  required.Add("cooking")
  required.Add("english")
  required.Add("math")
  required.Add("biology")

  // Create a string-based set of science classes.
  sciences := mapset.NewSet[string]()
  sciences.Add("biology")
  sciences.Add("chemistry")
  
  // Create a string-based set of electives.
  electives := mapset.NewSet[string]()
  electives.Add("welding")
  electives.Add("music")
  electives.Add("automotive")

  // Create a string-based set of bonus programming classes.
  bonus := mapset.NewSet[string]()
  bonus.Add("beginner go")
  bonus.Add("python for dummies")
}

Create a set of all unique classes. Sets will automatically deduplicate the same data.

  all := required
    .Union(sciences)
    .Union(electives)
    .Union(bonus)
  
  fmt.Println(all)

Output:

Set{cooking, english, math, chemistry, welding, biology, music, automotive, beginner go, python for dummies}

Is cooking considered a science class?

result := sciences.Contains("cooking")
fmt.Println(result)

Output:

false

Show me all classes that are not science classes, since I don't enjoy science.

notScience := all.Difference(sciences)
fmt.Println(notScience)
Set{ music, automotive, beginner go, python for dummies, cooking, english, math, welding }

Which science classes are also required classes?

reqScience := sciences.Intersect(required)

Output:

Set{biology}

How many bonus classes do you offer?

fmt.Println(bonus.Cardinality())

Output:

2

Thanks for visiting!

-deckarep