client_id,client_name,client_age
1,Jose,42
2,Daniel,26
3,Vincent,32

package main
import (
	"fmt"
	"os"
	"github.com/gocarina/gocsv"
)
type NotUsed struct {
	Name string
}
type Client struct { // Our example struct, you can use "-" to ignore a field
	Id            string `csv:"client_id"`
	Name          string `csv:"client_name"`
	Age           string `csv:"client_age"`
	NotUsedString string `csv:"-"`
	NotUsedStruct NotUsed `csv:"-"` 
}
func main() {
	clientsFile, err := os.OpenFile("clients.csv", os.O_RDWR|os.O_CREATE, os.ModePerm)
	if err != nil {
		panic(err)
	}
	defer clientsFile.Close()
	clients := []*Client{}
	if err := gocsv.UnmarshalFile(clientsFile, &clients); err != nil { // Load clients from file
		panic(err)
	}
	for _, client := range clients {
		fmt.Println("Hello", client.Name)
	}
}

package main
import (
	"fmt"
	"os"
	"github.com/gocarina/gocsv"
)
type NotUsed struct {
	Name string
}
type Client struct { // Our example struct, you can use "-" to ignore a field
	Id            string `csv:"client_id"`
	Name          string `csv:"client_name"`
	Age           string `csv:"client_age"`
	NotUsedString string `csv:"-"`
	NotUsedStruct NotUsed `csv:"-"` 
}
func main() {
	clientsFile, err := os.OpenFile("clients.csv", os.O_RDWR|os.O_CREATE, os.ModePerm)
	if err != nil {
		panic(err)
	}
	defer clientsFile.Close()
	clients := []*Client{}
	clients = append(clients, &Client{Id: "12", Name: "John", Age: "21"}) // Add clients
	clients = append(clients, &Client{Id: "13", Name: "Fred"})
	clients = append(clients, &Client{Id: "14", Name: "James", Age: "32"})
	clients = append(clients, &Client{Id: "15", Name: "Danny"})
	err = gocsv.MarshalFile(&clients, clientsFile) // Use this to save the CSV back to the file
	if err != nil {
		panic(err)
	}
}

type TypeMarshaller interface {
	MarshalCSV() (string, error)
}
// TypeUnmarshaller is implemented by any value that has an UnmarshalCSV method
// This converter is used to convert a string to your value representation of that string
type TypeUnmarshaller interface {
	UnmarshalCSV(string) error
}

// MarshalText encodes the receiver into UTF-8-encoded text and returns the result.
type TextMarshaler interface {
	MarshalText() (text []byte, err error)
}
type TextUnmarshaler interface {
	UnmarshalText(text []byte) error
}

type DateTime struct {
	time.Time
}
// Convert the internal date as CSV string
func (date *DateTime) MarshalCSV() (string, error) {
	return date.Time.Format("20060201"), nil
}
// You could also use the standard Stringer interface 
func (date *DateTime) String() (string) {
	return date.String() // Redundant, just for example
}
// Convert the CSV string as internal date
func (date *DateTime) UnmarshalCSV(csv string) (err error) {
	date.Time, err = time.Parse("20060201", csv)
	return err
}
type Client struct { // Our example struct with a custom type (DateTime)
	Id       string   `csv:"id"`
	Name     string   `csv:"name"`
	Employed DateTime `csv:"employed"`
}
func main() {
	client := []Client{
		{
			Id: "001",
			Name: "Go學堂",
			Employed: DateTime{time.Now()},
		},
	}
	csvContent, _ := gocsv.MarshalString(client)
	fmt.Println("csv:", csvContent) //輸出內(nèi)容是 001,Go學堂,20231003
}

gocsv.SetCSVReader(func(in io.Reader) gocsv.CSVReader {
    r := csv.NewReader(in)
	r.Comma = '|'
    return r // Allows use pipe as delimiter
})

gocsv.SetCSVWriter(func(out io.Writer) *gocsv.SafeCSVWriter {
	writer := csv.NewWriter(out)
    writer.Comma = '|'
    return gocsv.NewSafeCSVWriter(writer)
})