理解する必要がある主要な Golang データ処理方法とテクノロジー

package main

import "fmt"

func main() {
    colors := []string{"Red", "Green", "Blue"}
    fmt.Println(colors)

    // 添加元素
    colors = append(colors, "Yellow")
    fmt.Println(colors)

    // 切片操作
    subset := colors[1:3]
    fmt.Println(subset)
}

package main

import "fmt"

func main() {
    scores := map[string]int{
        "Alice": 90,
        "Bob":   85,
        "Cindy": 95,
    }

    // 添加元素
    scores["David"] = 88
    fmt.Println(scores)

    // 查找元素
    value, exists := scores["Bob"]
    fmt.Println(value, exists)

    // 删除元素
    delete(scores, "Cindy")
    fmt.Println(scores)
}

package main

import (
    "fmt"
    "time"
)

func printNumbers() {
    for i := 1; i <= 5; i++ {
        time.Sleep(1 * time.Second)
        fmt.Printf("%d ", i)
    }
}

func main() {
    go printNumbers()
    time.Sleep(6 * time.Second)
    fmt.Println("done")
}

package main

import (
    "encoding/json"
    "fmt"
)

type Person struct {
    Name string `json:"name"`
    Age  int    `json:"age"`
}

func main() {
    data := `{"name":"Alice","age":25}`
    var person Person
    json.Unmarshal([]byte(data), &person)
    fmt.Println(person)

    person.Age = 26
    newData, _ := json.Marshal(person)
    fmt.Println(string(newData))
}

package main

import (
    "database/sql"
    "fmt"
    _ "github.com/go-sql-driver/mysql"
)

func main() {
    db, err := sql.Open("mysql", "username:password@tcp(127.0.0.1:3306)/dbname")
    if err != nil {
        panic(err)
    }
    defer db.Close()

    // 查询数据
    rows, err := db.Query("SELECT id, name FROM users")
    if err != nil {
        panic(err)
    }
    defer rows.Close()

    for rows.Next() {
        var id int
        var name string
        err = rows.Scan(&id, &name)
        if err != nil {
            panic(err)
        }
        fmt.Println(id, name)
    }

    // 插入数据
    _, err = db.Exec("INSERT INTO users (name) VALUES (?)", "Alice")
    if err != nil {
        panic(err)
    }
}