英文:
Cannot loop through yaml.MapItem.Value in go
问题
我正在尝试解析一个 YAML 文件，并保持表格处理的顺序（由于外键问题）。
fixtures.yaml
table1:- id: 1field1: "some value"field2: "some value"table2:- id: 1field1: "some value"field2: "some value"...更多数据...
main.go
yamlContent, err := ioutil.ReadFile("fixtures.yaml")yamlOutput := yaml.MapSlice{}err := yaml.Unmarshal(yamlContent, &yamlOutput)if err != nil {log.Fatal(err)}for _, tableData := range yamlOutput {// 表格名称fmt.Println(tableData.Key)// 表格数据fmt.Println(tableData.Value)// 这里出错for _, row := range tableData.Value {fmt.Println(row)}}
tableData.Value 的值看起来像这样：
[[{id 1} {field1 some value} {field2 some value} {field3 some value} {field4 some value} {field5 some value}]]
问题是我无法遍历 tableData.Value。每当我尝试这样做时，都会出现错误：
cannot range over tableData.Value (type interface {})
但是，当我使用 reflect.TypeOf(tableData.Value) 时，我得到的是 []interface {}。
我应该怎么做才能循环遍历每一行，然后再遍历每一个键值对？我在 Go 中还是新手，所以不太确定接下来该怎么做。
英文:
I'm trying to parse a yaml file while keeping the order (due to foreign key issues) of tables being processed.
fixtures.yaml
table1:-id: 1field1: "some value"field2: "some value"table2:-id: 1field1: "some value"field2: "some value"...some more data...
main.go
yamlContent, err := ioutil.ReadFile("fixtures.yaml")yamlOutput := yaml.MapSlice{}err := yaml.Unmarshal(yamlContent, &yamlOutput)if err != nil {log.Fatal(err)}for _, tableData := range yamlOutput {//Table Namefmt.Println(tableData.Key)//Table Datafmt.Println(tableData.Value)// Error herefor _, row := range tableData.Value {fmt.Println(row)}}
The value of tableData.Value looks something like this:
[[{id 1} {field1 some value} {field2 some value} {field3 some value} {field4 some value} {field5 some value}]]
The problem is I cannot range through tableData.Value. Whenever I do, I get the error:
cannot range over tableData.Value (type interface {})
But whenever I use reflect.TypeOf(tableData.Value), I get []interface {}
What should I do to be able to loop through each row and then through each key value pair? I'm pretty new in Go so I'm not really sure what to do next.
答案1
得分: 1
如果你有一个静态类型为interface{}的值，其动态类型为[]interface{}，那么你需要对其进行type-assert，以便能够在切片上进行迭代。
if v, ok := tableData.Value.([]interface{}); ok {for _, row := range v {fmt.Println(row)}}
https://play.golang.org/p/D16JKPglcaW
英文:
If you have a value that has static type interface{} whose dynamic type is []interface{} then you have to type-assert it to the dynamic type to be able to range over the slice.
if v, ok := tableData.Value.([]interface{}); ok {for _, row := range v {fmt.Println(row)}}
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