v0.0.475 ArrGroupBy

langext/array.go

@@ -564,3 +564,18 @@ func ArrChunk[T any](arr []T, chunkSize int) [][]T {
 
 	return res
 }
+
+func ArrGroupBy[T1 any, T2 comparable](arr []T1, groupfunc func(v T1) T2) map[T2][]T1 {
+	r := make(map[T2][]T1)
+
+	for _, v := range arr {
+		key := groupfunc(v)
+		if _, ok := r[key]; ok {
+			r[key] = append(r[key], v)
+		} else {
+			r[key] = []T1{v}
+		}
+	}
+
+	return r
+}