Go Snippets

for.go

i := 1
for i <= 3 {
	fmt.Println(i)
	i = i + 1
}

for j := 7; j <= 9; j++ {
	fmt.Println(j)
}

for {
	fmt.Println("loop")
	break
}

for n := 0; n <= 5; n++ {
	if n%2 == 0 {
		continue
	}
	fmt.Println(n)
}

lint.sh

go list ./... | grep -v /vendor/ | xargs -L1 golint | wc -l

map.go

m := make(map[string]int)

m["k1"] = 7
m["k2"] = 13

fmt.Println("map:", m)

v1 := m["k1"]
fmt.Println("v1: ", v1)

fmt.Println("len:", len(m))

delete(m, "k2")
fmt.Println("map:", m)

_, prs := m["k2"]
fmt.Println("prs:", prs)

n := map[string]int{"foo": 1, "bar": 2}
fmt.Println("map:", n)

range.go

nums := []int{2, 3, 4}
sum := 0
for _, num := range nums {
	sum += num
}
fmt.Println("sum:", sum)

for i, num := range nums {
	if num == 3 {
		fmt.Println("index:", i)
	}
}

kvs := map[string]string{"a": "apple", "b": "banana"}
for k, v := range kvs {
	fmt.Printf("%s -> %s\n", k, v)
}

for k := range kvs {
	fmt.Println("key:", k)
}

for i, c := range "go" {
	fmt.Println(i, c)
}

slice.go

s := make([]string, 3)
fmt.Println("emp:", s)

s[0] = "a"
s[1] = "b"
s[2] = "c"
fmt.Println("set:", s)
fmt.Println("get:", s[2])

fmt.Println("len:", len(s))

s = append(s, "d")
s = append(s, "e", "f")
fmt.Println("apd:", s)

c := make([]string, len(s))
copy(c, s)
fmt.Println("cpy:", c)

l := s[2:5]
fmt.Println("sl1:", l)

l = s[:5]
fmt.Println("sl2:", l)

l = s[2:]
fmt.Println("sl3:", l)

t := []string{"g", "h", "i"}
fmt.Println("dcl:", t)

twoD := make([][]int, 3)
for i := 0; i < 3; i++ {
	innerLen := i + 1
	twoD[i] = make([]int, innerLen)
	for j := 0; j < innerLen; j++ {
		twoD[i][j] = i + j
	}
}
fmt.Println("2d: ", twoD)

struct.go

package main

import "fmt"

type person struct {
    name string
    age  int
}

func newPerson(name string) *person {

    p := person{name: name}
    p.age = 42
    return &p
}

func main() {

    fmt.Println(person{"Bob", 20})

    fmt.Println(person{name: "Alice", age: 30})

    fmt.Println(person{name: "Fred"})

    fmt.Println(&person{name: "Ann", age: 40})

    fmt.Println(newPerson("Jon"))

    s := person{name: "Sean", age: 50}
    fmt.Println(s.name)

    sp := &s
    fmt.Println(sp.age)

    sp.age = 51
    fmt.Println(sp.age)
}