diff --git a/codes.go b/codes.go
index 3bf6722..a26516c 100644
--- a/codes.go
+++ b/codes.go
@@ -30,8 +30,8 @@ func NewCodes(c *Client, filenames ...string) (*Codes, error) {
 
 	//如果没有指定文件名,则使用默认
 	defaultFilename := filepath.Join(DefaultDatabaseDir, "codes.db")
-	filename := conv.Default[string](defaultFilename, filenames...)
-	filename = conv.Select[string](filename == "", defaultFilename, filename)
+	filename := conv.Default(defaultFilename, filenames...)
+	filename = conv.Select(filename == "", defaultFilename, filename)
 
 	//如果文件夹不存在就创建
 	dir, _ := filepath.Split(filename)
@@ -121,7 +121,7 @@ func (this *Codes) GetName(code string) string {
 
 // GetStocks 获取股票代码,sh6xxx sz0xx sz30xx
 func (this *Codes) GetStocks(limits ...int) []string {
-	limit := conv.Default[int](-1, limits...)
+	limit := conv.Default(-1, limits...)
 	ls := []string(nil)
 	for _, m := range this.list {
 		code := m.FullCode()
@@ -135,6 +135,22 @@ func (this *Codes) GetStocks(limits ...int) []string {
 	return ls
 }
 
+// GetETFs 获取基金代码,sz159xxx,sh510xxx,sh511xxx
+func (this *Codes) GetETFs(limits ...int) []string {
+	limit := conv.Default(-1, limits...)
+	ls := []string(nil)
+	for _, m := range this.list {
+		code := m.FullCode()
+		if protocol.IsETF(code) {
+			ls = append(ls, code)
+		}
+		if limit > 0 && len(ls) >= limit {
+			break
+		}
+	}
+	return ls
+}
+
 func (this *Codes) Get(code string) *CodeModel {
 	return this.Map[code]
 }
diff --git a/protocol/unit.go b/protocol/unit.go
index 9b3fa13..cb42e4e 100644
--- a/protocol/unit.go
+++ b/protocol/unit.go
@@ -213,6 +213,24 @@ func IsStock(code string) bool {
 	return false
 }
 
+// IsETF 是否是基金,示例sz159558
+func IsETF(code string) bool {
+	if len(code) != 8 {
+		return false
+	}
+	code = strings.ToLower(code)
+	switch {
+	case code[0:2] == ExchangeSH.String() &&
+		(code[2:5] == "510" || code[2:5] == "511" || code[2:5] == "512" || code[2:5] == "513" || code[2:5] == "515"):
+		return true
+
+	case code[0:2] == ExchangeSZ.String() &&
+		(code[2:5] == "159"):
+		return true
+	}
+	return false
+}
+
 // AddPrefix 添加股票代码前缀,针对股票生效,例如000001,会增加前缀sz000001(平安银行),而不是sh000001(上证指数)
 func AddPrefix(code string) string {
 	if len(code) == 6 {