diff --git a/01.01 python 基础.ipynb b/01.01 python 基础.ipynb
index 59cb916..c064019 100644
--- a/01.01 python 基础.ipynb
+++ b/01.01 python 基础.ipynb
@@ -11,7 +11,7 @@
    "cell_type": "markdown",
    "metadata": {},
    "source": [
-    "## 1.1 Python 简介\n",
+    "## 1.1.1 Python 简介\n",
     "\n",
     "<img src=\"https://www.python.org/static/img/python-logo@2x.png\" width=300/> \n",
     "\n",
@@ -41,7 +41,7 @@
    "cell_type": "markdown",
    "metadata": {},
    "source": [
-    "## 1.2 数据类型\n",
+    "## 1.1.2 数据类型\n",
     "\n",
     "| 类型| 例子|\n",
     "| -----  | ----- |\n",
@@ -190,7 +190,39 @@
    "cell_type": "markdown",
    "metadata": {},
    "source": [
-    "## 1.3 字符串"
+    "数值型转字符串："
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "str(1)"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "字符串转数字型："
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "int('1')"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## 1.1.3 字符串"
    ]
   },
   {
@@ -365,7 +397,7 @@
    "cell_type": "markdown",
    "metadata": {},
    "source": [
-    "## 1.4 索引和分片\n",
+    "## 1.1.4 索引和分片\n",
     "\n",
     "### 索引\n",
     "\n",
@@ -441,7 +473,7 @@
    "cell_type": "markdown",
    "metadata": {},
    "source": [
-    "## 1.5 列表\n",
+    "## 1.1.5 列表\n",
     "\n",
     "列表是一个有序的序列。\n",
     "\n",
@@ -919,7 +951,7 @@
    "cell_type": "markdown",
    "metadata": {},
    "source": [
-    "## 1.6 字典\n",
+    "## 1.1.6 字典\n",
     "\n",
     "字典 `dictionary` ，在一些编程语言中也称为 `hash` ， `map` ，是一种由键值对组成的数据结构。\n",
     "\n",
@@ -1098,7 +1130,7 @@
    "cell_type": "markdown",
    "metadata": {},
    "source": [
-    "## 1.7 元组\n",
+    "## 1.1.7 元组\n",
     "\n",
     "元组`Tuple`也是个有序序列，但是元组是不可变的，用`()`生成。"
    ]
@@ -1154,7 +1186,26 @@
    "cell_type": "markdown",
    "metadata": {},
    "source": [
-    "## 1.8 集合"
+    "可以把元组转为列表："
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "a = (10, 11, 12, 13, 14)\n",
+    "b = list(a)\n",
+    "print(b)\n",
+    "type(b)"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## 1.1.8 集合"
    ]
   },
   {
@@ -1240,7 +1291,7 @@
    "cell_type": "markdown",
    "metadata": {},
    "source": [
-    "## 1.9 判断语句"
+    "## 1.1.9 判断语句"
    ]
   },
   {
@@ -1480,7 +1531,7 @@
    "cell_type": "markdown",
    "metadata": {},
    "source": [
-    "## 1.10 循环\n",
+    "## 1.1.10 循环\n",
     "\n",
     "循环的作用在于将一段代码重复执行多次。\n",
     "\n",
diff --git a/01.03 机器学习常用的包.ipynb b/01.03 机器学习常用的包.ipynb
index 0c37177..67764d2 100644
--- a/01.03 机器学习常用的包.ipynb
+++ b/01.03 机器学习常用的包.ipynb
@@ -1466,7 +1466,7 @@
     "fruits = ['apple', 'orange', 'pear']\n",
     "sales = [100,250,300]\n",
     "plt.pie(sales, labels=fruits)\n",
-    "plt.savefig('pie.jpg')\n",
+    "plt.savefig('pie.png')\n",
     "plt.show()\n"
    ]
   },