Go by Example: Reading Files

Go provides the os and bufio packages that make it easy to read files. Here’s an example of how you can read a file line by line in Go:

package main

import (
	"bufio"
	"fmt"
	"os"
)

func main() {
	// Open the file
	file, err := os.Open("test.txt")
	if err != nil {
		fmt.Println("Error opening file:", err)
		return
	}
	defer file.Close()

	// Create a scanner to read the file
	scanner := bufio.NewScanner(file)

	// Read the file line by line
	for scanner.Scan() {
		line := scanner.Text()
		fmt.Println(line)
	}

	// Check for errors while reading the file
	if err := scanner.Err(); err != nil {
		fmt.Println("Error reading file:", err)
	}
}

In this example, we first use the os.Open function to open the file "test.txt". The defer file.Close statement is used to ensure that the file is closed when the program finishes, even if there is an error.

Next, we use the bufio.NewScanner function to create a scanner that will read the file. The scanner has a Scan method that returns true as long as there is another line to read, and the Text method returns the current line as a string.

We use a for loop to read the file line by line, and we use the fmt.Println function to print each line.

Finally, we use the scanner.Err function to check for any errors that occurred while reading the file.