英文:
Iterating slice struct within struct using reflection
问题
我正在尝试实现以下内容：
使用案例：
- 我有三个结构体，我需要将其中的两个与另一个进行比较（在示例中描述为：需要将a和b与full进行比较）。
- 使用反射循环遍历每个字段，获取字段的名称。并比较a和full、b和full之间的差异，将结果存储在一个共享结构体中。
- 如果字段等于"World"，我们知道它是一个切片结构体：
- 我需要获取Foo结构体中Bar切片的第一个索引。
- 即使变量是一个切片，我知道在这个案例中它的长度始终为1。
- 获取后，我需要像前一个if语句中所发生的那样循环遍历这些字段。
示例代码：
type Foo struct {Hello stringWorld []Bar}type Bar struct {Fish string}type Result struct {Field stringCorrect_A boolDistance_A intCorrect_B boolDistance_B intResult []Result}func compare_structs() {var full, a, b Foo// 填充所有变量...result := []Result{}rfx_f := reflect.ValueOf(full)rfx_a := reflect.ValueOf(a)rfx_b := reflect.ValueOf(b)type_result := rfx_f.Type()for i := 0; i < rfx_f.NumField(); i++ {tmp_res := Result{Field: type_result.Field(i).Name,}if reflect.TypeOf(full).Field(i).Type.Kind() != reflect.Slice {value := rfx_f.Field(i).Interface()value_a := rfx_a.FieldByName(tmp_res.Field).Interface()value_b := rfx_b.FieldByName(tmp_res.Field).Interface()// 比较该字段的值的函数tmp_res.compare(value, value_a, value_b)tmp_res.lev(value, value_a, value_b)result = append(result, tmp_res)} else if tmp_res.Field == "World" {/*我需要获取Foo结构体中Bar切片的第一个索引。即使变量是一个切片，我知道在这个案例中它的长度始终为1。获取后，我需要像前一个if语句中所发生的那样循环遍历这些字段。*/}}}
英文:
I'm trying to achieve the following:
Use-case:
- I have three structures, I need to compare 2 of those against one. (in the example described as: a & b need to be compared against full)
- Reflection is used to loop over every field, retrieve the name of the field. And comparing the difference between a & full, b & full, storing the results in a shared structure.
- If the field equals World, we know it's a slice struct:
I need to retrieve the first index of the Bar slice within the Foo structure.
Even though the variable is a slice, I know it will always have a length of 1 in this use-case.
When retrieved I need to loop over those fields, like what is happening in the previous if statement.
Example code:
type Foo struct {Hello stringWorld []Bar}type Bar struct {Fish string}type Result struct {Field stringCorrect_A boolDistance_A intCorrect_B boolDistance_B intResult []Result}func compare_structs() {var full, a, b Foo// filling in all variables...result := []Result{}rfx_f := reflect.ValueOf(full)rfx_a := reflect.ValueOf(a)rfx_b := reflect.ValueOf(b)type_result := rfx_f.Type()for i := 0; i < rfx_f.NumField(); i++ {tmp_res := Result{Field: type_result.Field(i).Name,}if reflect.TypeOf(full).Field(i).Type.Kind() != reflect.Slice {value := rfx_f.Field(i).Interface()value_a := rfx_a.FieldByName(tmp_res.Field).Interface()value_b := rfx_b.FieldByName(tmp_res.Field).Interface()// functions to compare the values of this fieldtmp_res.compare(value, value_a, value_b)tmp_res.lev(value, value_a, value_b)result = append(result, tmp_res)} else if tmp_res.Field == "World" {/*I need to retrieve the first index of the Bar slice within the Foo structure.Even though the variable is a slice, I know it will always have a length of 1 in this use-case.When retrieved I need to loop over those fields, like what is happening in the previous if statement.*/}}}
答案1
得分: 1
你首先需要获取字段：
wordField := rfx_f.Field(i)
你知道它是一个切片，所以你可以通过索引来获取第一个元素：
item := wordField.Index(0)
如果索引超出范围，这将引发 panic。
然后你可以迭代字段：
for fieldIx := 0; fieldIx < item.NumField(); fieldIx++ {field := item.Field(fieldIx)}
英文:
You first need to get the field:
wordField:=rfx_f.Field(i)
which you know to be a slice, so you index it to get the first element
item:=wordField.Index(0)
This will panic if index is out of range.
Then you can iterate the fields:
for fieldIx:=0;fieldIx<item.NumField();fieldIx++ {field:=item.Field(fieldIx)}
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