fix bug

maps/map.go

@@ -40,10 +40,10 @@ func Merge[K comparable, V any](mm ...map[K]V) map[K]V {
 // 按照键值生成字符串
 func Join[K constraints.Ordered, V any](m Map[K, V], sep string, f func(k K, v V) string) string {
 	slice := make([]string, 0, m.Count())
-	for _, k := range m.Keys() {
-		v, _ := m.Get(k)
+
+	m.ForEach(func(k K, v V) {
 		slice = append(slice, f(k, v))
-	}
+	})
 
 	return strings.Join(slice, sep)
 }