Go snippets

1. Get random string in Go

import (
	"fmt"
	"math/rand"
)

var probLetters = []rune("abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ!@#$%^&*1234567890")

func randString(length int) string {
  b := make([]rune, length)

  for i := range b {
    b[i] = probLetters[rand.Intn(len(probLetters) - 1)]
  }

  return string(b)
}

fmt.Println(randString(10))

You can try here.

2. Scheduling with time.Sleep()

import (
	"time"
)

func doSomething() {}

for true {
  doSomething()
  time.Sleep(time.Second * 10)
}

The doSomething() will be invoked every 10 seconds.

3. Checking palindrome string

func isPalindrome(s string) bool {
	var letters []rune

	for _, r := range s {
		if unicode.IsLetter(r) {
			letters = append(letters, unicode.ToLower(r))
		}
	}

	for i := range letters {
		if letters[i] != letters[len(letters)-1-i] {
			return false
		}
	}

	return true
}

4. Fetching API with package net/http

func fetchAPI() {
	URL := "https://jsonplaceholder.typicode.com/posts"

	response, err := http.Get(URL)
	if err != nil {
		fmt.Printf("Error: %v\n", err)
		return
	}
	defer response.Body.Close()

	data, err := ioutil.ReadAll(response.Body)
	if err != nil {
		fmt.Printf("Error: %v\n", err)
		return
	}

	fmt.Print(string(data))
}

5. Padding string with certain character

func formatString(num int) string {
  formatted := fmt.Sprintf("%04d", num)

  return formatted
}

fmt.Println(formatString(5)) // Output: 0005

In the format string “%04d”, 0 specifies zero padding, and 4 specifies the width of the resulting string. So, %04d means format the number as a decimal integer (d) with a width of 4 characters, padded with zeros if necessary.

6. Prevent many goroutines access shared resources simultaneously

import (
    "sync"
)

var mu sync.Mutex

func processFunction() {
    // Lock the mutex before executing the function
    mu.Lock()
    defer mu.Unlock()
    
    // Simulate some work
    for i := 0; i < 5; i++ {
        fmt.Println(i)
    }
}

func main() {
	// Launch several goroutines to invoke the function
	for i := 0; i < 3; i++ {
		go processFunction()
	}
}