How can I skip the first line of a file in Go? - go

Question

How can I read a file in Go and skip the first line / headers?
In Python I know I could do
counter = 0
with open("my_file_path", "r") as fo:
try:
next(fo)
except:
pass
for _ in fo:
counter = counter + 1
This is my Go application
package main
import (
"bufio"
"flag"
"os"
)
func readFile(fileLocation string) int {
fileOpen, _ := os.Open(fileLocation)
defer fileOpen.Close()
fileScanner := bufio.NewScanner(fileOpen)
counter := 0
for fileScanner.Scan() {
//fmt.Println(fileScanner.Text())
counter = counter + 1
}
return counter
}
func main() {
fileLocation := flag.String("file_location", "default value", "file path to count lines")
flag.Parse()
counted := readFile(*fileLocation)
println(counted)
}
I will be reading a huge file and don't want to be evaluating each line if the index is 0.

Answer 1

How about to move to the next token before the loop
scanner := bufio.NewScanner(file)
scanner.Scan() // this moves to the next token
for scanner.Scan() {
fmt.Println(scanner.Text())
}
file
1
2
3
output
2
3
https://play.golang.org/p/I2w50zFdcg0

Answer 2

For example,
package main
import (
"bufio"
"fmt"
"os"
)
func readFile(filename string) (int, error) {
f, err := os.Open(filename)
if err != nil {
return 0, err
}
defer f.Close()
count := 0
s := bufio.NewScanner(f)
if s.Scan() {
for s.Scan() {
count++
}
}
if err := s.Err(); err != nil {
return 0, err
}
return count, nil
}
func main() {
filename := `test.file`
count, err := readFile(filename)
if err != nil {
fmt.Fprintln(os.Stderr, err)
return
}
fmt.Println(count)
}
Output:
$ cat test.file
1234567890
abc
$ go run count.go
1
$

Answer 3

you can try something like this
func readFile(fileLocation string) int {
fileOpen, _ := os.Open(fileLocation)
defer fileOpen.Close()
fileScanner := bufio.NewScanner(fileOpen)
counter := 0
for fileScanner.Scan() {
// read first line and ignore
fileScanner.Text()
break
}
for fileScanner.Scan() {
// read remaining lines and process
txt := fileScanner.Text()
counter = counter + 1
// do something with text
}
return counter
}
Edit:
func readFile(fileLocation string) int {
fileOpen, _ := os.Open(fileLocation)
defer fileOpen.Close()
fileScanner := bufio.NewScanner(fileOpen)
counter := 0
if fileScanner.Scan() {
// read first line and ignore
fileScanner.Text()
}
for fileScanner.Scan() {
// read remaining lines and process
txt := fileScanner.Text()
// do something with text
counter = counter + 1
}
return counter
}