diff --git a/README b/README
index 3ab0ebd..a21f810 100644
--- a/README
+++ b/README
@@ -81,5 +81,3 @@ gobyexample.com signups
 * time
 * oauth for google domains
 * connection pool
-* ruby enumerable
-* ruby string
diff --git a/src/xx-enumerable.go b/src/xx-enumerable.go
new file mode 100644
index 0000000..bc76c37
--- /dev/null
+++ b/src/xx-enumerable.go
@@ -0,0 +1,90 @@
+package main
+
+import ("fmt"; "strings")
+
+func Index(elems []string, val string) int {
+	for i, v := range elems {
+		if v == val {
+			return i
+		}
+	}
+	return -1
+}
+
+func Include(elems []string, val string) bool {
+	return Index(elems, val) >= 0
+}
+
+func Any(elems []string, f func(string)bool) bool {
+	for _, v := range elems {
+		if f(v) {
+			return true
+		}
+	}
+	return false
+}
+
+func All(elems []string, f func(string)bool) bool {
+	for _, v := range elems {
+		if !f(v) {
+			return false
+		}
+	}
+	return true
+}
+
+func Filter(elems []string, f func(string)bool) []string {
+	filtered := []string{}
+	for _, v := range elems {
+		if f(v) {
+			filtered = append(filtered, v)
+		}
+	}
+	return filtered
+}
+
+func Map(elems []string, f func(string)string) []string {
+	mapped := make([]string, len(elems))
+	for i, v := range elems {
+		mapped[i] = f(v)
+	}
+	return mapped
+}
+
+func main() {
+	var elems = []string{"peach", "apple", "pear", "banana"}
+
+	fmt.Println(Index(elems, "pear"))
+	fmt.Println(Index(elems, "grape"))
+	fmt.Println()
+
+	fmt.Println(Include(elems, "pear"))
+	fmt.Println(Include(elems, "grape"))
+	fmt.Println()
+
+	fmt.Println(Any(elems, func(v string) bool {
+		return strings.HasPrefix(v, "p")
+	}))
+	fmt.Println(Any(elems, func(v string) bool {
+		return strings.HasPrefix(v, "g")
+	}))
+	fmt.Println()
+
+	fmt.Println(All(elems, func(v string) bool {
+		return strings.Contains(v, "a")
+	}))
+	fmt.Println(All(elems, func(v string) bool {
+		return strings.Contains(v, "p")
+	}))
+	fmt.Println()
+
+	fmt.Println(Filter(elems, func(v string) bool {
+		return strings.Contains(v, "p")
+	}))
+	fmt.Println()
+	
+	fmt.Println(Map(elems, func(s string) string {
+		return strings.ToUpper(s)
+	}))
+	fmt.Println()
+}