Go Package bufio

External

• https://pkg.go.dev/bufio

Internal

• Standard Library
• File Operations in Go

Overview

The bufio package is aimed at buffering input in something faster (memory) while interacting with something slower (disk). bufio is useful in situations when queueing improves the overall system performance.

Reading a Text File Line by Line

With Scanner

import (
	"bufio"
	"os"
)

f, err := os.Open("/Users/ovidiu/tmp/sometext.txt")
if err != nil {
  ...
}
defer f.Close()
scanner := bufio.NewScanner(f)
scanner.Split(bufio.ScanLines)
for scanner.Scan() {
  line := scanner.Text()
  ...
}

With Reader

ReadLine() returns io.EOF on end of file.

f, err := os.Open(...)
r := bufio.NewReader(f)
for {
	lineb, _, err := r.ReadLine()
	if err != nil {
		if errors.Is(err, io.EOF) {
			fmt.Printf("is End of File!\n")
        } else {
		    fmt.Printf("%v\n", err)
		}
		break
	} else {
		fmt.Printf("%s\n", string(lineb))
	}
}