golang read file line by line

To read a file line by line in Go, you can follow these steps:

Open the file: To open a file in Go, you can use the os.Open() function, which takes the file path as an argument and returns a pointer to a File object. You can handle any errors that occur during the file opening process using the if err != nil pattern.
Create a scanner: Once the file is open, you can create a scanner to read the file line by line. The bufio.NewScanner() function takes a Reader object, which can be obtained by calling the bufio.NewReader() function and passing the opened file as an argument. This will return a Scanner object.
Read lines: To read lines from the file, you can use the Scanner.Scan() method in a loop. This method reads the next line from the file and returns true if a line is successfully scanned, or false if there are no more lines to be read or if an error occurs. You can access the scanned line by calling the Scanner.Text() method.
Process the line: Inside the loop where you read the lines, you can process each line according to your requirements. You can perform any necessary operations or manipulations on the line data.
Close the file: Once you have finished reading the file, it is good practice to close it using the File.Close() method. This helps free up system resources and ensures that the file is properly closed.

Here's an example code snippet that demonstrates how to read a file line by line in Go:

package main

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

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

    // Create a scanner
    scanner := bufio.NewScanner(bufio.NewReader(file))

    // Read lines
    for scanner.Scan() {
        line := scanner.Text()

        // Process the line
        fmt.Println(line)
    }

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

In this example, the code opens a file named "file.txt" and reads it line by line using a scanner. Each line is printed to the console. Any errors that occur during the file opening or scanning process are handled and displayed accordingly.