Features

var flag bool
var count int64
var ratio float32
var student1 string = "John" //type is string
var student2 = "Jane" //type is inferred
x := 2

var a, b, c, d int = 1, 3, 5, 7
e, f := 100, "World!"

var (
  g int
  h int = 1
  i string = "hello"
)

const (
  PI = 3.14
  MAX_COUNT = 10000
)

// Initialize only specific elements
arr1 := [5]int{1:10,2:40}

// Find the length of an array
arrLen := len(arr1)

mySlice := []int{}

// Create a slice from an array
myArr := [6]int{10, 11, 12, 13, 14,15}
mySlice := myArr[2:4]

// Create a slice with the make()
// slice_name := make([]type, length, capacity)
mySlice := make([]int, 5)

// Append elements to a slice
mySlice = append(mySlice, 20, 21)

// Append one slice to another slice
mySlice1 := []int{1,2,3}
mySlice2 := []int{4,5,6}
mySlice3 := append(mySlice1, mySlice2)

// Create copy with only needed numbers
numbers := []int{1,2,3,4,5,6,7,8,9,10,11,12,13,14,15}
neededNumbers := numbers[:len(numbers)-10]
numbersCopy := make([]int, len(neededNumbers))
copy(numbersCopy, neededNumbers)

myMap := map[string]int{"Oslo": 1, "Bergen": 2, "Trondheim": 3, "Stavanger": 4}

// Create maps using make()
myMap := make(map[string]int)

// Remove element from map
delete(myMap, "year")

//Check for specific elements in a map
_, ok := myMap["model"]

// Use range to iterate over maps
for k, v := range myMap {
  fmt.Printf("%v : %v\n", k, v)
}

type Person struct {
  name string
  age int
  job string
  salary int
}

fruits := [3]string{"apple", "orange", "banana"}
for idx, val := range fruits {
  fmt.Printf("%v\t%v\n", idx, val)
}

func myFunction(x int, y int) int {
  return x + y
}

// Named return values
func myFunction(x int, y int) (result int) {
  result = x + y
  return
}

// Multiple return values
func myFunction(x int, y string) (result int, txt1 string) {
  result = x + x
  txt1 = y + " World!"
  return
}
a, b := myFunction(5, "Hello")

func Map[T1, T2 any](arr []T1, fn func(T1) T2) []T2 {
    newArr := make([]T2, len(arr))
    for i := 0; i < len(arr); i++ {
        newArr[i] = fn(arr[i])
    }
    return newArr
}

func main() {
    names := []string{"Evan", "OMG", "Andy"}
    lens := Map(names, func(s string) int { return len(s) })
    fmt.Println(lens)  // [4 3 4]
}

go test -v -cover ./...

go test -bench=^BenchmarkSum$