287 lines
7.0 KiB
Plaintext
287 lines
7.0 KiB
Plaintext
{
|
||
"cells": [
|
||
{
|
||
"cell_type": "markdown",
|
||
"metadata": {},
|
||
"source": [
|
||
"# Python不需要显式的指定变量和函数的类型"
|
||
]
|
||
},
|
||
{
|
||
"cell_type": "code",
|
||
"execution_count": null,
|
||
"metadata": {},
|
||
"outputs": [],
|
||
"source": [
|
||
"a = '1' # a为str类型\n",
|
||
"b = '2' # b为str类型\n",
|
||
"b = 3 # b可以被直接修改为int类型\n",
|
||
"\n",
|
||
"print(a+b) # 报错：不同数据类型之间不能运算，说明python是强类型的\n",
|
||
"\n",
|
||
"# 函数定义也不需要声明返回值和参数的类型\n",
|
||
"def plus(a, b):\n",
|
||
" return a+b"
|
||
]
|
||
},
|
||
{
|
||
"cell_type": "markdown",
|
||
"metadata": {},
|
||
"source": [
|
||
"# Python的基础数据类型\n",
|
||
"**注意：基础数据类型均为保留关键字，不要这些关键字作为变量名！**"
|
||
]
|
||
},
|
||
{
|
||
"cell_type": "code",
|
||
"execution_count": null,
|
||
"metadata": {},
|
||
"outputs": [],
|
||
"source": [
|
||
"x = 1 # 合理\n",
|
||
"print(int)\n",
|
||
"int = 1 # 不合理但也不报错\n",
|
||
"print(int)"
|
||
]
|
||
},
|
||
{
|
||
"cell_type": "markdown",
|
||
"metadata": {},
|
||
"source": [
|
||
"## 1. 整数类型（`int`）\n",
|
||
"## 2. 浮点数类型（`float`）\n",
|
||
"## 3. 布尔类型（`bool`）\n",
|
||
"## 4. 列表类型（`list`）"
|
||
]
|
||
},
|
||
{
|
||
"cell_type": "code",
|
||
"execution_count": null,
|
||
"metadata": {},
|
||
"outputs": [],
|
||
"source": [
|
||
"my_list = [1, 2, 3, \"hello\"]\n",
|
||
"print(type(my_list)) # 输出: <class 'list'>\n",
|
||
"\n",
|
||
"# 访问元素\n",
|
||
"print(my_list[0]) # 输出: 1\n",
|
||
"print(my_list[-1]) # 输出: \"hello\"\n",
|
||
"print(my_list[0:2]) # 输出: [1, 2]，要头不要尾\n",
|
||
"\n",
|
||
"# 修改元素\n",
|
||
"my_list[0] = 'modified'\n",
|
||
"print(my_list) # ['modified', 2, 3, \"hello\"]"
|
||
]
|
||
},
|
||
{
|
||
"cell_type": "code",
|
||
"execution_count": null,
|
||
"metadata": {},
|
||
"outputs": [],
|
||
"source": [
|
||
"# 添加元素\n",
|
||
"my_list.append('append') \n",
|
||
"print(\"my_list.append:\", my_list) # ['modified', 2, 3, \"hello\", 'append']\n",
|
||
"my_list.insert(1, 'insert')\n",
|
||
"print(\"my_list.insert:\", my_list) # ['modified', 'insert', 2, 3, \"hello\", 4]\n",
|
||
"\n",
|
||
"# 删除元素\n",
|
||
"my_list.remove('modified')\n",
|
||
"print(\"my_list.remove:\", my_list) # ['insert', 2, 3, \"hello\", 4]\n",
|
||
"my_list.pop(3)\n",
|
||
"print(\"my_list.pop:\", my_list) # ['insert', 2, 3, 4]\n",
|
||
"\n",
|
||
"# 查找元素\n",
|
||
"print(\"2 in my_list:\")\n",
|
||
"print(2 in my_list) # 输出：True\n",
|
||
"print(\"9 in my_list:\")\n",
|
||
"print(9 in my_list) # 输出：False\n",
|
||
"print(\"my_list.index(2):\")\n",
|
||
"print(my_list.index(2)) # 输出：1\n",
|
||
"print(\"my_list.index(9):\")\n",
|
||
"print(my_list.index(9)) # 直接抛异常"
|
||
]
|
||
},
|
||
{
|
||
"cell_type": "markdown",
|
||
"metadata": {},
|
||
"source": [
|
||
"## 5. 字符串类型（`str`）"
|
||
]
|
||
},
|
||
{
|
||
"cell_type": "code",
|
||
"execution_count": null,
|
||
"metadata": {},
|
||
"outputs": [],
|
||
"source": [
|
||
"name = \"Python\"\n",
|
||
"name = 'Python' # 单引号和双引号在python里都表示字符串，没有任何区别"
|
||
]
|
||
},
|
||
{
|
||
"cell_type": "markdown",
|
||
"metadata": {},
|
||
"source": [
|
||
"## 6. 元组类型（`tuple`）\n",
|
||
"## 7. 集合类型（`set`）"
|
||
]
|
||
},
|
||
{
|
||
"cell_type": "code",
|
||
"execution_count": null,
|
||
"metadata": {},
|
||
"outputs": [],
|
||
"source": [
|
||
"my_set = {'one', 'two', 'three', 'three', 'four'}\n",
|
||
"print(my_set) # 输出: {'one', 'two', 'three', 'four'}?"
|
||
]
|
||
},
|
||
{
|
||
"cell_type": "code",
|
||
"execution_count": null,
|
||
"metadata": {},
|
||
"outputs": [],
|
||
"source": [
|
||
"my_set.add('five')\n",
|
||
"print(my_set) # 输出: {'one', 'two', 'three', 'four', 'five'}"
|
||
]
|
||
},
|
||
{
|
||
"cell_type": "code",
|
||
"execution_count": null,
|
||
"metadata": {},
|
||
"outputs": [],
|
||
"source": [
|
||
"my_set.remove('five')\n",
|
||
"print(my_set) # 输出: {'one', 'two', 'three', 'four'}?\n",
|
||
"my_set.pop()\n",
|
||
"print(my_set) # 输出: {'two', 'three', 'four'}?"
|
||
]
|
||
},
|
||
{
|
||
"cell_type": "code",
|
||
"execution_count": null,
|
||
"metadata": {},
|
||
"outputs": [],
|
||
"source": [
|
||
"print(my_set[0]) \t # 直接报错：集合是无序的，不能按下标取值\n",
|
||
"print('two' in my_set) # 输出：True。集合通常就是这么用的，用来判断一个值在不在集合里。"
|
||
]
|
||
},
|
||
{
|
||
"cell_type": "markdown",
|
||
"metadata": {},
|
||
"source": [
|
||
"## 8. 字典类型（`dict`）\n",
|
||
"键-值对的无序集合，且**键不可重复**。类似于哈希表。"
|
||
]
|
||
},
|
||
{
|
||
"cell_type": "code",
|
||
"execution_count": 4,
|
||
"metadata": {},
|
||
"outputs": [],
|
||
"source": [
|
||
"my_dict = {\"name\": \"Alice\", \"age\": 25}"
|
||
]
|
||
},
|
||
{
|
||
"cell_type": "markdown",
|
||
"metadata": {},
|
||
"source": [
|
||
"## 9. None 类型"
|
||
]
|
||
},
|
||
{
|
||
"cell_type": "markdown",
|
||
"metadata": {},
|
||
"source": [
|
||
"# 条件控制语句\n",
|
||
"## 1. 任何版本都通用：if语句"
|
||
]
|
||
},
|
||
{
|
||
"cell_type": "code",
|
||
"execution_count": 5,
|
||
"metadata": {},
|
||
"outputs": [],
|
||
"source": [
|
||
"def positive_or_negative(a, b):\n",
|
||
" if a > 0:\n",
|
||
" print(\"It's positive.\")\n",
|
||
" if a == 0:\n",
|
||
" print(\"It's zero!\")\n",
|
||
" else:\n",
|
||
" print(\"It's negative.\")"
|
||
]
|
||
},
|
||
{
|
||
"cell_type": "code",
|
||
"execution_count": null,
|
||
"metadata": {},
|
||
"outputs": [],
|
||
"source": [
|
||
"# 下面是一段错误代码\n",
|
||
"def describe_temperature(temp):\n",
|
||
" if temp >= 30:\n",
|
||
" print(\"It's a hot day!\")\n",
|
||
" if temp >= 20:\n",
|
||
" print(\"It's a warm day.\")\n",
|
||
" if temp >= 10:\n",
|
||
" print(\"It's a cool day.\")\n",
|
||
" else:\n",
|
||
" print(\"It's a cold day.\")"
|
||
]
|
||
},
|
||
{
|
||
"cell_type": "markdown",
|
||
"metadata": {},
|
||
"source": [
|
||
"## 2. Python 3.10+ 新特性：match-case语句"
|
||
]
|
||
},
|
||
{
|
||
"cell_type": "code",
|
||
"execution_count": null,
|
||
"metadata": {},
|
||
"outputs": [],
|
||
"source": [
|
||
"def fruit_description(fruit):\n",
|
||
" match fruit:\n",
|
||
" case \"apple\":\n",
|
||
" print(\"This is a red or green fruit, usually sweet.\")\n",
|
||
" case \"banana\":\n",
|
||
" print(\"This is a long, yellow fruit, and it is soft.\")\n",
|
||
" case \"orange\":\n",
|
||
" print(\"This is a round orange fruit, and it is juicy\")\n",
|
||
" case \"grape\":\n",
|
||
" print(\"This is a small fruit.\")\n",
|
||
" case _:\n",
|
||
" print(\"I don't know this fruit.\")"
|
||
]
|
||
}
|
||
],
|
||
"metadata": {
|
||
"kernelspec": {
|
||
"display_name": "python",
|
||
"language": "python",
|
||
"name": "python3"
|
||
},
|
||
"language_info": {
|
||
"codemirror_mode": {
|
||
"name": "ipython",
|
||
"version": 3
|
||
},
|
||
"file_extension": ".py",
|
||
"mimetype": "text/x-python",
|
||
"name": "python",
|
||
"nbconvert_exporter": "python",
|
||
"pygments_lexer": "ipython3",
|
||
"version": "3.11.10"
|
||
}
|
||
},
|
||
"nbformat": 4,
|
||
"nbformat_minor": 2
|
||
}
|