diff --git a/args.go b/args.go
index af4b3e9..d20689f 100644
--- a/args.go
+++ b/args.go
@@ -6,7 +6,6 @@
 	"strings"
 )
 
-
 func main() {
 	fmt.Printf("args: %+v\n", os.Args)
 	fmt.Printf("args: %+v\n", os.Args[1:])
diff --git a/array.go b/array.go
new file mode 100644
index 0000000..b6a9115
--- /dev/null
+++ b/array.go
@@ -0,0 +1,31 @@
+package main
+
+import "fmt"
+
+func main() {
+	var a[3]int // 要素の値を省略したらゼロ値
+	fmt.Printf("a: %+v\n", a) // [0, 0, 0]
+	b := [3]int{1, 2, 3}
+	fmt.Printf("b: %+v\n", b) // [1, 2, 3]
+	c := [3]int{1, 2}
+	fmt.Printf("c: %+v\n", c) // [1, 2, 0]
+	d := [3]int{2: 2}
+	fmt.Printf("d: %+v\n", d) // [0, 0, 2]
+	e := [3]int{0:1, 1: 2}
+	fmt.Printf("e: %+v\n", e) // [1, 2, 0]
+
+	// 要素が比較可能であればその配列型も比較可能
+	fmt.Printf("a==b: %v\n", a == b) // false
+	fmt.Printf("c==e: %v\n", c == e) // true
+	// f := [4]int{}
+	// fmt.Printf("a==f: %v\n", a == f) // compile error: [3]int == [4]int
+
+	hoge(a)
+	fmt.Printf("a: %+v\n", a) // [0, 0, 0]
+}
+
+func hoge(arg [3]int) { 
+	arg[0] = 4
+	fmt.Printf("%+v\n", arg) // [4, 0, 0]
+	// 値渡しなので安全だが性能的に非効率なことがある
+}
diff --git a/array/README.md b/array/README.md
new file mode 100644
index 0000000..be7bbf5
--- /dev/null
+++ b/array/README.md
@@ -0,0 +1,12 @@
+## array.go
+
+配列
+
+## slice.go
+
+スライス
+
+## append.go
+
+append関数の使い方や仕組み
+
diff --git a/array/append b/array/append
new file mode 100755
index 0000000..0425a76
--- /dev/null
+++ b/array/append
Binary files differ
diff --git a/array/append.go b/array/append.go
new file mode 100644
index 0000000..cda34dd
--- /dev/null
+++ b/array/append.go
@@ -0,0 +1,24 @@
+package main
+
+import "fmt"
+
+func main() {
+	ary := []int{}
+	for i := 0; i < 10; i++ {
+		ary = append(ary, i)
+		fmt.Printf("%d: %p len:%d cap:%d %v\n", i, ary, len(ary), cap(ary), ary)
+	}
+	/*
+	   0: 0x140000180b8 len:1 cap:1 [0]
+	   1: 0x140000180e0 len:2 cap:2 [0 1]
+	   2: 0x1400001e040 len:3 cap:4 [0 1 2]
+	   3: 0x1400001e040 len:4 cap:4 [0 1 2 3]
+	   4: 0x14000014100 len:5 cap:8 [0 1 2 3 4]
+	   5: 0x14000014100 len:6 cap:8 [0 1 2 3 4 5]
+	   6: 0x14000014100 len:7 cap:8 [0 1 2 3 4 5 6]
+	   7: 0x14000014100 len:8 cap:8 [0 1 2 3 4 5 6 7]
+	   8: 0x1400006e000 len:9 cap:16 [0 1 2 3 4 5 6 7 8]
+	   9: 0x1400006e000 len:10 cap:16 [0 1 2 3 4 5 6 7 8 9]
+	*/
+}
+
diff --git a/array/append.go~ b/array/append.go~
new file mode 100644
index 0000000..b213107
--- /dev/null
+++ b/array/append.go~
@@ -0,0 +1,24 @@
+package main
+
+import "fmt"
+
+func main() {
+	ary := []int{}
+	for i := 0; i < 10; i++ {
+		ary = append(ary, i)
+		fmt.Printf("%d: %p cap:%d %v\n", i, ary,  cap(ary), ary)
+	}
+	/*
+	   0: 0x14000134008 cap:1 [0]
+	   1: 0x14000134030 cap:2 [0 1]
+	   2: 0x1400013a020 cap:4 [0 1 2]
+	   3: 0x1400013a020 cap:4 [0 1 2 3]
+	   4: 0x1400012c080 cap:8 [0 1 2 3 4]
+	   5: 0x1400012c080 cap:8 [0 1 2 3 4 5]
+	   6: 0x1400012c080 cap:8 [0 1 2 3 4 5 6]
+	   7: 0x1400012c080 cap:8 [0 1 2 3 4 5 6 7]
+	   8: 0x1400013c000 cap:16 [0 1 2 3 4 5 6 7 8]
+	   9: 0x1400013c000 cap:16 [0 1 2 3 4 5 6 7 8 9]
+	*/
+}
+
diff --git a/array/array.go b/array/array.go
new file mode 100644
index 0000000..9cd6461
--- /dev/null
+++ b/array/array.go
@@ -0,0 +1,31 @@
+package main
+
+import "fmt"
+
+func main() {
+	var a[3]int // 要素の値を省略したらゼロ値
+	fmt.Printf("a: %+v\n", a) // [0, 0, 0]
+	b := [3]int{1, 2, 3}
+	fmt.Printf("b: %+v\n", b) // [1, 2, 3]
+	c := [3]int{1, 2}
+	fmt.Printf("c: %+v\n", c) // [1, 2, 0]
+	d := [3]int{2: 2}
+	fmt.Printf("d: %+v\n", d) // [0, 0, 2]
+	e := [3]int{0:1, 1: 2}
+	fmt.Printf("e: %+v\n", e) // [1, 2, 0]
+
+	// 要素が比較可能であればその配列型も比較可能
+	fmt.Printf("a==b: %v\n", a == b) // false
+	fmt.Printf("c==e: %v\n", c == e) // true
+	// f := [4]int{}
+	// fmt.Printf("a==f: %v\n", a == f) // compile error: [3]int == [4]int
+
+	hoge(a)
+	fmt.Printf("a: %+v\n", a) // [0, 0, 0]
+	// 値渡しなので安全だが性能的に非効率なことがある
+}
+
+func hoge(arg [3]int) { 
+	arg[0] = 4
+	fmt.Printf("%+v\n", arg) // [4, 0, 0]
+}
diff --git a/array/slice.go b/array/slice.go
new file mode 100644
index 0000000..705cb07
--- /dev/null
+++ b/array/slice.go
@@ -0,0 +1,16 @@
+package main
+
+import "fmt"
+
+func main() {
+	s := []string{0:"", 1:"Jan", 2:"Feb", 3:"Mar", 4:"Apr", 5:"May", 6:"Jun", 7:"Jul", 8:"Aug", 9:"Sep", 10:"Oct", 11:"Nov", 12:"Dec"}
+	fmt.Printf("%d\n", len(s)) // 13(0-12)
+	fmt.Printf("%+v\n", s[2:4]) // [Feb Mar]
+	fmt.Printf("%d\n", len(s[2:4])) // 2
+	fmt.Printf("%d\n", cap(s[2:4])) // 11(2-12)
+	fmt.Printf("%+v\n", s[2:7]) // [Feb Mar Apr May Jun]
+	fmt.Printf("%d\n", len(s[2:7])) // 5
+	fmt.Printf("%d\n", cap(s[2:7])) // 11(2-12)
+	fmt.Printf("%+v\n", s[:]) // [ Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec]
+}
+
diff --git a/hello.go b/hello.go
index 0cf4e8c..0261c49 100644
--- a/hello.go
+++ b/hello.go
@@ -2,7 +2,6 @@
 
 import "fmt"
 
-
 func main() {
 	fmt.Println("Hello, World")
 }
diff --git a/slice.go b/slice.go
new file mode 100644
index 0000000..1d533ad
--- /dev/null
+++ b/slice.go
@@ -0,0 +1,9 @@
+package main
+
+import "fmt"
+
+func main() {
+
+	fmt.Println("Hello, World")
+}
+