To write a file in Golang, you can use the “io.WriteString()” function. The “os.Create()” function creates or truncates a file and the io.Writer interface provides a way to write data to the file. The os.File type implements the io.Writer interface, so you can use it directly to write data to the file.
Example
package main
import (
"fmt"
"io"
"log"
"os"
)
func main() {
// Define the file path
filePath := "my_data_file.txt"
// Create or truncate the file
file, err := os.Create(filePath)
if err != nil {
log.Fatalf("Error creating file: %v", err)
}
defer file.Close()
// Define the data to be written to the file
data := "Hello, Golang!\n"
// Write the data to the file
n, err := io.WriteString(file, data)
if err != nil {
log.Fatalf("Error writing to file: %v", err)
}
fmt.Printf("Successfully wrote %d bytes to %s\n", n, filePath)
}Output
Successfully wrote 15 bytes to my_data_file.txt
In this code, we defined the file path as example.txt and used the “os.Create()” function to create or truncate the file. We then defined the data to be written to the file as string data.
In the next step, we used the “io.WriteString()” function to write the data to the file. Finally, we print a success message indicating the number of bytes written to the file.
Go write to file with File.Write/File.WriteAt
To write to a file, you can use the os.Create() function to create a new file, and then call the Write() or WriteAt() method of the returned *os.File object.
package main
import (
"log"
"os"
)
func main() {
// Create a new file
file, err := os.Create("test.txt")
if err != nil {
log.Fatal(err)
}
defer file.Close()
// Write some text to the file
byteSlice := []byte("Hello, World!")
offset := int64(5) // Start writing at position 5
bytesWritten, err := file.WriteAt(byteSlice, offset)
if err != nil {
log.Fatal(err)
}
log.Printf("Wrote %d bytes.\n", bytesWritten)
}Output
2023/07/14 16:34:56 Wrote 13 bytes.Go write to file with ioutil.WriteFile
In Go, the ioutil.WriteFile() function is a convenient way to write a byte slice directly to a file. It handles opening, writing to, and closing the file, all in one function call.
package main
import (
"io/ioutil"
"log"
)
func main() {
// Define the data to write to the file.
data := []byte("Hello, World!")
// Write the data to the file.
err := ioutil.WriteFile("text.txt", data, 0644)
if err != nil {
log.Fatal(err)
}
log.Println("File written successfully")
}Output
2023/07/14 16:36:42 File written successfullyThat’s it.
Krunal Lathiya is a seasoned Computer Science expert with over eight years in the tech industry. He boasts deep knowledge in Data Science and Machine Learning. Versed in Python, JavaScript, PHP, R, and Golang. Skilled in frameworks like Angular and React and platforms such as Node.js. His expertise spans both front-end and back-end development. His proficiency in the Python language stands as a testament to his versatility and commitment to the craft.
