diff --git a/xx-sortby.go b/xx-sortby.go
new file mode 100644
index 0000000..712a71a
--- /dev/null
+++ b/xx-sortby.go
@@ -0,0 +1,48 @@
+package main
+
+import ("fmt" ; "sort")
+
+type Person struct { 
+    Name string
+    Age int
+}
+
+type ByName []Person
+func (this ByName) Len() int {
+    return len(this)
+}
+func (this ByName) Less(i, j int) bool {
+    return this[i].Name < this[j].Name
+}
+func (this ByName) Swap(i, j int) {
+    this[i], this[j] = this[j], this[i]
+}
+
+type ByAge []Person
+func (this ByAge) Len() int {
+	return len(this)
+}
+func (this ByAge) Less(i, j int) bool {
+    return this[i].Age < this[j].Age
+}
+func (this ByAge) Swap(i, j int) {
+    this[i], this[j] = this[j], this[i]
+}
+
+func main() {
+    kids := []Person{
+		{"Jack", 10},
+        {"Jill", 9},
+        {"Bob",  12},
+    }
+    fmt.Println("Original:", kids)
+	fmt.Println()
+	
+	sort.Sort(ByName(kids))
+	fmt.Println("ByName:  ", kids)
+	fmt.Println()
+
+	sort.Sort(ByAge(kids))
+	fmt.Println("ByAge:   ", kids)
+	fmt.Println()
+}