Golang read text file

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Read Text File in Golang

1. read line by line

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func main() {
   f, err := os.Open("demo.txt")
   if err != nil {
      fmt.Println("err:", err)
      return
   }
   defer f.Close()

   content, err := readTxt(f)
   if err != nil {
      fmt.Println("err:", err)
      return
   }
   fmt.Println("content:", content)
}

func readTxt(r io.Reader) ([]string, error) {
   reader := bufio.NewReader(r)

   l := make([]string, 0, 64)

   // 按行读取
   for {
      line, _, err := reader.ReadLine()
      if err != nil {
         if err == io.EOF {
            break
         } else {
            return nil, err
         }
      }

      l = append(l, strings.Trim(string(line), " "))
   }

   return l, nil
}

2. read all content at once

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func main() {
   f, err := os.Open("demo.txt")
   if err != nil {
      fmt.Println("err:", err)
      return
   }
   defer f.Close()

   content, err := readAllContent(f)
   if err != nil {
      fmt.Println("err:", err)
      return
   }
   fmt.Println("content:", content)
}

func readAllContent(r io.Reader) ([]string, error) {
   var b = make([]byte, 4096)
   _, err := r.Read(b)
   if err != nil {
      return nil, err
   }

   l := strings.Split(string(b), "\r\n")
   return l, nil
}