Collection of Golang novice questions: Solve common problems and move towards improvement

In response to common problems faced by Golang novices, this article provides a clear solution: define and initialize the structure: type Person struct { Name string; Age int }; Person p = {"John Doe", 30} using mapping: m: = make(map[string]int); m["Alice"] = 10 Processing a variable number of parameters: func sumAll(...int) int Reading and writing files: File opening, writing, reading Creating and using Goroutine: go concurrentFunc(i)

Golang novice question collection: solve common problems and move towards improvement

As a novice in Golang, it is very difficult to It is easy to encounter various problems. This article will help newbies get better at it by providing clear and easy-to-understand solutions to some of the most common frustrations.

1. How to define and initialize a structure?

type Person struct {
  Name string
  Age  int
}

p := Person{"John Doe", 30}

2. How to use mapping (Map)?

m := make(map[string]int)
m["Alice"] = 10
m["Bob"] = 20

fmt.Println(m["Alice"]) // 输出: 10

3. How to receive a variable number of parameters?

func sumAll(numbers ...int) int {
  total := 0
  for _, num := range numbers {
    total += num
  }
  return total
}

result := sumAll(1, 2, 3, 4, 5) // result = 15

4. How to read and write files?

f, err := os.Open("test.txt")
if err != nil {
  panic(err)
}
defer f.Close()

_, err = f.Write([]byte("Hello, world!"))
if err != nil {
  panic(err)
}

b := make([]byte, 10)
_, err = f.Read(b)
if err != nil {
  panic(err)
}
fmt.Println(string(b)) // 输出: "Hello, wo"

5. How to create and use Goroutine?

func concurrentFunc(i int) {
  fmt.Println(i)
}

for i := 0; i < 5; i++ {
  go concurrentFunc(i)
}
// 同时输出 0、1、2、3、4

Practical Case

Suppose we want to create a simple RESTful API that allows users to manage tasks.

1. Define the task structure:

type Task struct {
  ID   int
  Name string
  Desc string
}

2. Create a task collection:

tasks := make([]Task, 0)

3. Process creation task request:

func createTask(w http.ResponseWriter, r *http.Request) {
  var task Task
  if err := json.NewDecoder(r.Body).Decode(&task); err != nil {
    http.Error(w, "Invalid JSON", http.StatusBadRequest)
    return
  }

  tasks = append(tasks, task)
  fmt.Fprint(w, "Task created successfully")
}

4. Process acquisition task request:

func getTasks(w http.ResponseWriter, r *http.Request) {
  enc := json.NewEncoder(w)
  if err := enc.Encode(tasks); err != nil {
    http.Error(w, "Failed to encode tasks", http.StatusInternalServerError)
    return
  }
}

5. Start HTTP server:

func main() {
  http.HandleFunc("/tasks", createTask)
  http.HandleFunc("/tasks", getTasks)

  fmt.Println("Server listening on port 8080")
  if err := http.ListenAndServe(":8080", nil); err != nil {
    panic(err)
  }
}

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