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package csvutil_test
import (
"bytes"
"encoding/csv"
"fmt"
"strconv"
"time"
"github.com/jszwec/csvutil"
)
func ExampleEncoder_Encode_streaming() {
type Address struct {
City string
Country string
}
type User struct {
Name string
Address
Age int `csv:"age,omitempty"`
}
users := []User{
{Name: "John", Address: Address{"Boston", "USA"}, Age: 26},
{Name: "Bob", Address: Address{"LA", "USA"}, Age: 27},
{Name: "Alice", Address: Address{"SF", "USA"}},
}
var buf bytes.Buffer
w := csv.NewWriter(&buf)
enc := csvutil.NewEncoder(w)
for _, u := range users {
if err := enc.Encode(u); err != nil {
fmt.Println("error:", err)
}
}
w.Flush()
if err := w.Error(); err != nil {
fmt.Println("error:", err)
}
fmt.Println(buf.String())
// Output:
// Name,City,Country,age
// John,Boston,USA,26
// Bob,LA,USA,27
// Alice,SF,USA,
}
func ExampleEncoder_Encode_all() {
type Address struct {
City string
Country string
}
type User struct {
Name string
Address
Age int `csv:"age,omitempty"`
}
users := []User{
{Name: "John", Address: Address{"Boston", "USA"}, Age: 26},
{Name: "Bob", Address: Address{"LA", "USA"}, Age: 27},
{Name: "Alice", Address: Address{"SF", "USA"}},
}
var buf bytes.Buffer
w := csv.NewWriter(&buf)
if err := csvutil.NewEncoder(w).Encode(users); err != nil {
fmt.Println("error:", err)
}
w.Flush()
if err := w.Error(); err != nil {
fmt.Println("error:", err)
}
fmt.Println(buf.String())
// Output:
// Name,City,Country,age
// John,Boston,USA,26
// Bob,LA,USA,27
// Alice,SF,USA,
}
func ExampleEncoder_EncodeHeader() {
type User struct {
Name string
Age int `csv:"age,omitempty"`
}
var buf bytes.Buffer
w := csv.NewWriter(&buf)
enc := csvutil.NewEncoder(w)
if err := enc.EncodeHeader(User{}); err != nil {
fmt.Println("error:", err)
}
w.Flush()
if err := w.Error(); err != nil {
fmt.Println("error:", err)
}
fmt.Println(buf.String())
// Output:
// Name,age
}
func ExampleEncoder_Encode_inline() {
type Owner struct {
Name string `csv:"name"`
}
type Address struct {
Street string `csv:"street"`
City string `csv:"city"`
Owner Owner `csv:"owner_,inline"`
}
type User struct {
Name string `csv:"name"`
Address Address `csv:",inline"`
HomeAddress Address `csv:"home_address_,inline"`
WorkAddress Address `csv:"work_address_,inline"`
Age int `csv:"age,omitempty"`
}
users := []User{
{
Name: "John",
Address: Address{"Washington", "Boston", Owner{"Steve"}},
HomeAddress: Address{"Boylston", "Boston", Owner{"Steve"}},
WorkAddress: Address{"River St", "Cambridge", Owner{"Steve"}},
Age: 26,
},
}
b, err := csvutil.Marshal(users)
if err != nil {
fmt.Println("error:", err)
}
fmt.Printf("%s\n", b)
// Output:
// name,street,city,owner_name,home_address_street,home_address_city,home_address_owner_name,work_address_street,work_address_city,work_address_owner_name,age
// John,Washington,Boston,Steve,Boylston,Boston,Steve,River St,Cambridge,Steve,26
}
func ExampleEncoder_Register() {
type Foo struct {
Time time.Time `csv:"time"`
Hex int `csv:"hex"`
PtrHex *int `csv:"ptr_hex"`
Buffer *bytes.Buffer `csv:"buffer"`
}
foos := []Foo{
{
Time: time.Date(2020, 6, 20, 12, 0, 0, 0, time.UTC),
Hex: 15,
Buffer: bytes.NewBufferString("hello"),
},
}
marshalInt := func(n *int) ([]byte, error) {
if n == nil {
return []byte("NULL"), nil
}
return strconv.AppendInt(nil, int64(*n), 16), nil
}
marshalTime := func(t time.Time) ([]byte, error) {
return t.AppendFormat(nil, time.Kitchen), nil
}
// all fields which implement String method will use this, unless their
// concrete type was already overriden.
marshalStringer := func(s fmt.Stringer) ([]byte, error) {
return []byte(s.String()), nil
}
var buf bytes.Buffer
w := csv.NewWriter(&buf)
enc := csvutil.NewEncoder(w)
enc.Register(marshalInt)
enc.Register(marshalTime)
enc.Register(marshalStringer)
if err := enc.Encode(foos); err != nil {
fmt.Println("error:", err)
}
w.Flush()
if err := w.Error(); err != nil {
fmt.Println("error:", err)
}
fmt.Println(buf.String())
// Output:
// time,hex,ptr_hex,buffer
// 12:00PM,f,NULL,hello
}
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