custom-SplitFunc-in-golang.go

package main

import (
	"bufio"
	"bytes"
	"fmt"
	"strings"
)

//func check(e err) {
//	if e != nil {
//		log.Panic(e)
//	}
//}

// Custom split function. This will split string at 'sbustring' i.e # or // etc....
func SplitAt(substring string) func(data []byte, atEOF bool) (advance int, token []byte, err error) {
	searchBytes := []byte(substring)
	searchLength := len(substring)
	return func(data []byte, atEOF bool) (advance int, token []byte, err error) {
		dataLen := len(data)

		// Return Nothing if at the end of file or no data passed.
		if atEOF && dataLen == 0 {
			return 0,nil,nil
		}

		// Find next separator and return token.
		if i := bytes.Index(data, searchBytes); i >= 0 {
			return i + searchLength, data[0:i], nil
		}

		// If we're at EOF, we have a final, non-terminated line. Return it.
		if atEOF {
			return dataLen, data, nil
		}

		// Request more data.
		return 0, nil, nil
	}
}

func main() {
	const input = "123# \n237 93829938#34823\n56873264"
	scanner := bufio.NewScanner(strings.NewReader(input))

	scanner.Split(SplitAt("\n"))
	// Validate the input
	for scanner.Scan() {
		fmt.Printf("%s\n", scanner.Text())
	}

	if err := scanner.Err(); err != nil {
		fmt.Printf("Invalid input: %s", err)
	}
}