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https://github.com/tobyhede/Go-underscore

Helpfully Functional Go - A useful collection of Go utilities. Designed for programmer happiness.
https://github.com/tobyhede/Go-underscore

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Helpfully Functional Go - A useful collection of Go utilities. Designed for programmer happiness.

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README 

        
Underscore.go

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Move Fast; Optimize Late

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A useful collection of Go utilities. Designed for programmer happiness.



TL;DR Sort-of like underscore.js, but for Go



API Documentation

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[GoDoc is WorkInProgress](https://godoc.org/github.com/tobyhede/go-underscore)



:warning: Warning

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This package is in heavy flux at the moment as I work to incorporate feedback from various sources.



:squirrel: Todo

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- [ ] godoc

- [ ] contains

- [ ] indexOf

- [ ] worker pools

- [x] parallel each

- [x] parallel map with worker pool

- [x] refactor to make functions first parameter (eg Each func(func(A), []A))

- [x] handle maps & slices

- [x] all

- [x] any

- [x] none



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* [Notes on Typed Functions](#typed)

* [Any](#any)

* [Each](#each)

* [Every](#every)

* [Map](#map)

* [None](#none)



### Typed Functions ###

---------------------------------------------------------------------------



### Any ###

---------------------------------------------------------------------------



### Each ###

---------------------------------------------------------------------------



Each func(func(A int), []A)

Each func(func(A B), []A)



Applies the given iterator function to each element of a collection (slice or map).



If the collection is a Slice, the iterator function arguments are *value, index*



If the collection is a Map, the iterator function arguments are *value, key*



EachP is a Parallel implementation of Each and *concurrently* applies the given iterator function to each element of a collection (slice or map).



``` go

  // var Each func(func(value interface{}, i interface{}), interface{})



  var buffer bytes.Buffer



  fn := func(s, i interface{}) {

    buffer.WriteString(s.(string))

  }



  s := []string{"a", "b", "c", "d", "e"}

  Each(fn, s)



  expect := "abcde"



  e := un.Each(fn, s)



  fmt.Printf("%#v\n", e) //"abcde"

```



Typed Each can be defined using a function type and the *MakeEach* helper.



Using a Typed Slice



``` go

  var EachInt func(func(value, i int), []int)

  MakeEach(&EachInt)



  var sum int



  fn := func(v, i int) {

    sum += v

  }



  i := []int{1, 2, 3, 4, 5}

  EachInt(fn, i)



  fmt.Printf("%#v\n", sum) //15

```



Using a Typed Map

``` go

  var EachStringInt func(func(key string, value int), map[string]int)

  var sum int



  fn := func(v int, k string) {

    sum += v

  }



  m := map[string]int{"a": 1, "b": 2, "c": 3, "d": 4, "e": 5}

  EachStringInt(fn, m)



  fmt.Printf("%#v\n", sum) //15

```



Of note is the ability to close over variables within the calling scope.



### Every ###

---------------------------------------------------------------------------



### Map ###

---------------------------------------------------------------------------



``` go

Map func([]A, func(A) B) []B

```



Applies the given function to each element of a slice, returning a slice of results



The base Map function accepts interface{} types and returns []interface{}



``` go

  // Map func(interface{}, func(interface{}) interface{}) []interface{}



  s := []string{"a", "b", "c", "d"}



  fn := func(s interface{}) interface{} {

    return s.(string) + "!"

  }



  m := un.Map(ToI(s), fn)

  fmt.Println(m) //["a!", "b!", "c!", "d!"]

```



Typed Maps can be defined using a function type and the *MakeMap* helper.



``` go

  Map func([]A, func(A) B) []B



  var SMap func([]string, func(string) string) []string

  un.MakeMap(&SMap)



  m := un.SMap(s, fn)

  fmt.Println(m) //["a!", "b!", "c!", "d!"]

```



Of note is the return value of Map is a slice of the return type of the applied function.



### Partition ###

---------------------------------------------------------------------------



Partition func([]A, func(A) bool) ([]A []A)



Partition splits a slice or map based on the evaluation of the supplied function



The base Partition function accepts interface{} types and returns []interface{}



``` go

  // Partition func(interface{}, func(interface{}) bool) ([]interface{}, []interface{})



  s := []int{1, 2, 3, 4, 5, 6, 7, 8, 9, 10}



  fn := func(i interface{}) bool {

    return (i.(int) % 2) == 1

  }



  odd, even := un.Partition(s, fn)



  fmt.Println(odd)  //[1, 3, 5, 7, 9]

  fmt.Println(even) //[2, 4, 6, 8, 10]

```



Typed Partitions can be defined using a function type and the *MakePartition* helper.



``` go

  // Partition func([]A, func(A) bool) ([]A []A)



  var IPartition func([]int, func(int) bool) ([]int, []int)



  un.MakePartition(&IPartition)



  s := []int{1, 2, 3, 4, 5, 6, 7, 8, 9, 10}



  fn := func(i int) bool {

    return (i % 2) == 1

  }



  odd, even := un.IPartition(s, fn)



  fmt.Println(odd)  //[1, 3, 5, 7, 9]

  fmt.Println(even) //[2, 4, 6, 8, 10]

```



Contains returns true if an object is in a slice.



``` go

  o := "a"

  s := []string{"a", "b", "c"}



  b := un.Contains(s, o)

  fmt.Println(b) //true

```



ToI converts a slice of arbitrary type []T into a slice of []interfaces{}



``` go

  s := []int{1, 1, 3, 5, 8, 13}

  i := un.ToI(s)

```



Notes

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I am aware that the whole idea is not particularly very TheGoWay™, but it is useful as a learning exercise, and it is useful for moving fast and optimising later.