reflect通過包從切片結構中的子字段獲取項目數時，我遇到了一些問題。這就是我試圖從中獲取項目數量的方式Itemsfunc main() { type Items struct { Name string `json:"name"` Present bool `json:"present"` } type someStuff struct { Fields string `json:"fields"` Items []Items `json:"items"` } type Stuff struct { Stuff []someStuff `json:"stuff"` } some_stuff := `{ "stuff": [ { "fields": "example", "items": [ { "name": "book01", "present": true }, { "name": "book02", "present": true }, { "name": "book03", "present": true } ] } ] }` var variable Stuff err := json.Unmarshal([]byte(some_stuff), &variable) if err != nil { panic(err) } //I want to get the number of items in my case 3 NumItems := reflect.ValueOf(variable.Stuff.Items)}這是錯誤：variable.Items undefined (type []Stuff has no field or method Items)我不確定我是否可以檢索到這樣的項目數量。
1 回答
慕田峪7331174
TA貢獻1828條經驗 獲得超13個贊
我已經解決了這個問題。
為了獲得子字段的數量，我們可以使用Len()from reflect.ValueOf。
現在的代碼正在獲取項目的數量：
package main
import (
"encoding/json"
"fmt"
"reflect"
)
func main() {
type Items struct {
Name string `json:"name"`
Present bool `json:"present"`
}
type someStuff struct {
Fields string `json:"fields"`
Items []Items `json:"items"`
}
type Stuff struct {
Stuff []someStuff `json:"stuff"`
}
some_stuff := `{
"stuff": [
{
"fields": "example",
"items": [
{ "name": "book01", "present": true },
{ "name": "book02", "present": true },
{ "name": "book03", "present": true }
]
}
]
}`
var variable Stuff
err := json.Unmarshal([]byte(some_stuff), &variable)
if err != nil {
panic(err)
}
//I want to get the number of items in my case 3
t := reflect.ValueOf(variable.Stuff[0].Items)
fmt.Println(t.Len())
}
Output: 3
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