mapix · July 25, 2016 06:09 · Jul 25, 2016
diff --git a/shuffle.go b/shuffle.go
@@ -0,0 +1,42 @@
+package main
+
+import (
+	"fmt"
+	"math/rand"
+	"time"
+)
+
+func main() {
+	// shuffle local
+	hosts := []string{"a", "b", "c", "d", "e", "f"}
+	shuffle(len(hosts), func(i, j int) {
+		hosts[i], hosts[j] = hosts[j], hosts[i]
+	})
+
+	fmt.Println("shuffle string: ", hosts)
+
+	ints := []int{1, 2, 3, 4, 5, 6}
+	shuffle(len(ints), func(i, j int) {
+		ints[i], ints[j] = ints[j], ints[i]
+	})
+	fmt.Println("shuffle int: ", ints)
+
+	// shuffle new
+	nhosts := []string{"a", "b", "c", "d", "e", "f"}
+	new_nhosts := make([]string, len(nhosts))
+	copy(new_nhosts, nhosts)
+	shuffle(len(hosts), func(i, j int) {
+		new_nhosts[i], new_nhosts[j] = new_nhosts[j], new_nhosts[i]
+	})
+
+	fmt.Println("origin : ", nhosts)
+	fmt.Println("new : ", new_nhosts)
+}
+
+func shuffle(length int, exchange func(int, int)) {
+	rand.Seed(int64(time.Now().Nanosecond()))
+	for i := length - 1; i > 0; i-- {
+		j := rand.Intn(i)
+		exchange(i, j)
+	}
+}