Decode JSON
Examples
Filter
Go offers built-in support for JSON encoding and decoding, including to and from built-in and custom data types.
package main
import (
"encoding/json"
"fmt"
"os"
)
type response1 struct {
Page int
Fruits []string
}
type response2 struct {
Page int `json:"page"`
Fruits []string `json:"fruits"`
}
func main() {
bolB, _ := json.Marshal(true)
fmt.Println(string(bolB))
intB, _ := json.Marshal(1)
fmt.Println(string(intB))
fltB, _ := json.Marshal(2.34)
fmt.Println(string(fltB))
strB, _ := json.Marshal("gopher")
fmt.Println(string(strB))
slcD := []string{"apple", "peach", "pear"}
slcB, _ := json.Marshal(slcD)
fmt.Println(string(slcB))
mapD := map[string]int{"apple": 5, "lettuce": 7}
mapB, _ := json.Marshal(mapD)
fmt.Println(string(mapB))
res1D := &response1{
Page: 1,
Fruits: []string{"apple", "peach", "pear"}}
res1B, _ := json.Marshal(res1D)
fmt.Println(string(res1B))
res2D := &response2{
Page: 1,
Fruits: []string{"apple", "peach", "pear"}}
res2B, _ := json.Marshal(res2D)
fmt.Println(string(res2B))
byt := []byte(`{"num":6.13,"strs":["a","b"]}`)
var dat map[string]interface{}
if err := json.Unmarshal(byt, &dat); err != nil {
panic(err)
}
fmt.Println(dat)
num := dat["num"].(float64)
fmt.Println(num)
strs := dat["strs"].([]interface{})
str1 := strs[0].(string)
fmt.Println(str1)
str := `{"page": 1, "fruits": ["apple", "peach"]}`
res := response2{}
json.Unmarshal([]byte(str), &res)
fmt.Println(res)
fmt.Println(res.Fruits[0])
enc := json.NewEncoder(os.Stdout)
d := map[string]int{"apple": 5, "lettuce": 7}
enc.Encode(d)
}
Last Run
:
true
1
2.34
"gopher"
["apple","peach","pear"]
{"apple":5,"lettuce":7}
{"Page":1,"Fruits":["apple","peach","pear"]}
{"page":1,"fruits":["apple","peach","pear"]}
map[num:6.13 strs:[a b]]
6.13
a
{1 [apple peach]}
apple
{"apple":5,"lettuce":7}
// JSON is very popular nowadays, that's why JSON support is built in.
// The first argument of the json.decode function is the type to decode to.
// The second argument is the JSON string.
// V generates code for JSON encoding and decoding. No runtime reflection is used.
// This results in much better performance.
import json
struct Foo {
bar int
}
struct User {
name string
age int
// Use the `skip` attribute to skip certain fields
foo Foo [skip]
// If the field name is different in JSON, it can be specified
last_name string [json:lastName]
}
data := '{ "name": "Frodo", "lastName": "Baggins", "age": 25 }'
user := json.decode(User, data) or {
eprintln('Failed to decode json')
return
}
println(user.name)
println(user.last_name)
println(user.age)
Last Run
:
V panic: array.get: index out of range (i == -1, a.len == 0)
| 0x55c616e21dd2 | /code/root/v/v(+0x4dd2)
| 0x55c616e20a7d | /code/root/v/v(+0x3a7d)
| 0x55c616e8d883 | /code/root/v/v(+0x70883)
| 0x55c616e86754 | /code/root/v/v(+0x69754)
| 0x55c616e9d910 | /code/root/v/v(+0x80910)
| 0x55c616e9cfa1 | /code/root/v/v(+0x7ffa1)
| 0x55c616e9c853 | /code/root/v/v(+0x7f853)
| 0x55c616e820b7 | /code/root/v/v(+0x650b7)
| 0x55c616e9b7c3 | /code/root/v/v(+0x7e7c3)
| 0x55c616e989f5 | /code/root/v/v(+0x7b9f5)
| 0x55c616e9807a | /code/root/v/v(+0x7b07a)
| 0x55c616ead4b0 | /code/root/v/v(+0x904b0)
| 0x55c616e7c73e | /code/root/v/v(+0x5f73e)
| 0x55c616e7a72b | /code/root/v/v(+0x5d72b)
| 0x55c616e759ee | /code/root/v/v(+0x589ee)
| 0x55c616eb824c | /code/root/v/v(+0x9b24c)
| 0x55c616eb84e1 | /code/root/v/v(+0x9b4e1)
| 0x55c616eda430 | /code/root/v/v(+0xbd430)
| 0x55c616edfd02 | /code/root/v/v(+0xc2d02)
| 0x55c616eeae44 | /code/root/v/v(+0xcde44)
| 0x7fd08f36fb97 | /lib/x86_64-linux-gnu/libc.so.6(__libc_start_main+0xe7)
| 0x55c616e1fbba | /code/root/v/v(+0x2bba)