backend

utils/collect/collect.go

@@ -0,0 +1,82 @@
+package collect
+
+import (
+	"reflect"
+	"strconv"
+)
+
+func ArrayColumn[R any, T any](arr []T, column string) []R {
+	var result []R
+	s := reflect.ValueOf(arr)
+
+	for i := 0; i < s.Len(); i++ {
+		e := s.Index(i)
+		k := e.FieldByName(column)
+		result = append(result, k.Interface().(R))
+	}
+
+	return result
+}
+
+func ArrayIndex[T any](arr []T, index int) (result T, ok bool) {
+	if index < len(arr) {
+		result = arr[index]
+		ok = true
+		return
+	}
+	ok = false
+	return
+}
+
+func ArrayString2Int(arr interface{}) (result []int64) {
+	for _, a := range arr.([]string) {
+		v, err := strconv.ParseInt(a, 10, 64)
+		if err != nil {
+			panic(err)
+		}
+		result = append(result, v)
+	}
+	return result
+}
+
+func Array2MapByKey[KEY comparable, VALUE any](arrSrc []VALUE, fieldName string) (result map[KEY]VALUE) {
+	result = make(map[KEY]VALUE)
+	arr := reflect.ValueOf(arrSrc)
+
+	for i := 0; i < arr.Len(); i++ {
+		srcv := arr.Index(i)
+		fv := srcv.Elem().FieldByName(fieldName)
+		k := fv.Interface().(KEY)
+		result[k] = srcv.Interface().(VALUE)
+	}
+
+	return result
+}
+
+func Array2MapByKeyTag[KEY comparable, VALUE any](arrSrc []VALUE, tag string) (result map[KEY]VALUE) {
+
+	arr := reflect.ValueOf(arrSrc)
+
+	if arr.Len() == 0 {
+		return result
+	}
+	result = make(map[KEY]VALUE)
+
+	eleType := arr.Index(0).Elem().Type()
+
+	for j := 0; j < eleType.NumField(); j++ {
+		if value, ok := eleType.Field(j).Tag.Lookup("json"); ok && value == tag {
+
+			for i := 0; i < arr.Len(); i++ {
+				srcv := arr.Index(i)
+				fv := srcv.Elem().Field(j)
+				k := fv.Interface().(KEY)
+				result[k] = srcv.Interface().(VALUE)
+			}
+
+			return
+		}
+	}
+
+	return result
+}

utils/collect/collect_test.go

@@ -0,0 +1,32 @@
+package collect
+
+import (
+	"log"
+	"testing"
+)
+
+type ABC struct {
+	A int64       `json:"a"`
+	B string      `json:"b"`
+	C interface{} `json:"c"`
+}
+
+func TestArray2MapByKey(t *testing.T) {
+	var abcs []*ABC = []*ABC{
+		{1, "2", 3},
+		{3, "1", 2},
+	}
+	a := Array2MapByKey[string](abcs, "B")
+	log.Printf("%##v", a)
+	log.Println(len(a))
+}
+
+func TestArray2MapByKeyTag(t *testing.T) {
+	var abcs []*ABC = []*ABC{
+		{1, "2", 3},
+		{3, "1", 2},
+	}
+	a := Array2MapByKeyTag[int64](abcs, "a")
+	log.Printf("%##v", a)
+	log.Println(len(a))
+}