【Go】構造体サンプルメモ

サンプル

package main

import "fmt"

type Person struct {
	name string
	age int
}

func main() {
	// 宣言の後、値を代入
	var person1 Person
	person1.name = "Akira"
	person1.age = 20
	fmt.Println(person1)

	// 宣言＋代入
	person2 := Person{age: 30, name: "Kure"}
	fmt.Println(person2)

	// 宣言＋代入
	person3 := Person{"Aki", 40}
	fmt.Println(person3)
}

package main

import (
	"fmt"
	"encoding/json"
)

func main() {
	type location struct {
		Name string
		Lat float64
		Long float64
	}

	// JSON 変換するためにキーを大文字にしておく必要がある
	locations := []location {
		{Name: "Brandbury Landing", Lat: -4.5895, Long: 137.4417},
		{Name: "Columbia Memorial Station", Lat: -14.56684, Long: 175.472636},
		{Name: "Challenger Memorial Station", Lat: -1.9462, Long: 354.4734},
	}

	// [{Brandbury Landing -4.5895 137.4417} {Columbia Memorial Station -14.56684 175.472636} {Challenger Memorial Station -1.9462 354.4734}]
	fmt.Println(locations)

	b, _ := json.Marshal(locations)
	// [{"Name":"Brandbury Landing","Lat":-4.5895,"Long":137.4417},{"Name":"Columbia Memorial Station","Lat":-14.56684,"Long":175.472636},{"Name":"Challenger Memorial Station","Lat":-1.9462,"Long":354.4734}]
	fmt.Println(string(b))

	// JSONキーを指定
	type location2 struct {
		Name string `json:"name"`
		Lat float64 `json:"lat"`
		Long float64 `json:"long"`
	}

	locations2 := []location2 {
		{Name: "Brandbury Landing", Lat: -4.5895, Long: 137.4417},
		{Name: "Columbia Memorial Station", Lat: -14.56684, Long: 175.472636},
		{Name: "Challenger Memorial Station", Lat: -1.9462, Long: 354.4734},
	}

	// [{Brandbury Landing -4.5895 137.4417} {Columbia Memorial Station -14.56684 175.472636} {Challenger Memorial Station -1.9462 354.4734}]
	fmt.Println(locations2)

	c, _ := json.MarshalIndent(locations2, "", "  ")
  //	[
  //  {
  //    "name": "Brandbury Landing",
  //    "lat": -4.5895,
  //    "long": 137.4417
  //  },
  //  {
  //    "name": "Columbia Memorial Station",
  //    "lat": -14.56684,
  //    "long": 175.472636
  //  },
  //  {
  //    "name": "Challenger Memorial Station",
  //    "lat": -1.9462,
  //    "long": 354.4734
  //  }
  //]
	fmt.Println(string(c))
}

参考

改訂2版 基礎からわかる Go言語

posted with amazlet at 20.02.15

古川 昇
シーアンドアール研究所 (2015-07-17)
売り上げランキング: 201,077

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