打开cmd窗口，检查python环境，需要python3.7版本及以上
然后输入，下载requests库
pip install requests -i http://pypi.douban.com/simple/ --trusted-host pypi.douban.com
创建python文件，最好不要含有中文字符
# 1.导入模块
# 1.导入模块
import requests
# 2. 发送请求，获取响应
response = requests.get("http://www.baidu.com")
print(response) # 这里打印的结果是响应码
# 3. 获取响应数据
# print(response.encoding) # ISO-8859-1
# response.encoding = 'utf-8' # 设置编码格式
# print(response.text)
# 上面两句话等于下面一句话
print(response.content.decode())
运行结果：
案例代码：
# 1. 导入模块
import requests
# 2. 发送请求，获取响应
response = requests.get("https://ncov.dxy.cn/ncovh5/view/pneumonia")
# 3. 从响应中获取数据
print(response.content.decode())
运行结果：
Beautiful Soup 是一个可以从HTML或XML文件中提取数据的Python库.它能够通过你喜欢的转换器实现惯用的文档导航,查找,修改文档的方式.Beautiful Soup会帮你节省数小时甚至数天的工作时间.
运行下面两行命令，或者pycharm可以自动安装。
pip install bs4
pip install lxml
# 1. 导入模块
from bs4 import BeautifulSoup
# 2. 创建BeautifulSoup对象
soup = BeautifulSoup('<html>data</html>', 'lxml')
print(soup)
案例代码：
# 1.导入模块
from bs4 import BeautifulSoup
# 2.准备文本字符串
html = '''
<title>The Dormouse's story</title>
</head>
<body>
<p class="title">
<b>The Dormouse's story</b>
</p>
<p class="story">Once Upon a time three were three little sister;and their names were
<a href="http://example.com/elsie" class="sister" id="link1">Elsie</a>,
<a href="http://example.com/lacie" class="sister" id="link2">Lacie</a>and
<a href="http://example.com/tillie" class="sister" id="link3">Tillie</a>;
and they lived at the bottom of a well.
</p>
<p class="story">...</p>
</body>
</html>
'''
# 3.创建BeautifulSoup对象
soup = BeautifulSoup(html,'lxml')
# 4.查找title标签
title = soup.find('title')
print(title)
# 5.查找a标签
a = soup.find('a')
print(a)
#查找所有a标签
a_s = soup.find_all('a')
print(a_s)
运行结果：
案例代码
# 1.导入模块
from bs4 import BeautifulSoup
# 2.准备文本字符串
html = '''
<title>The Dormouse's story</title>
</head>
<body>
<p class="title">
<b>The Dormouse's story</b>
</p>
<p class="story">Once Upon a time three were three little sister;and their names were
<a href="http://example.com/elsie" class="sister" id="link1">Elsie</a>,
<a href="http://example.com/lacie" class="sister" id="link2">Lacie</a>and
<a href="http://example.com/tillie" class="sister" id="link3">Tillie</a>;
and they lived at the bottom of a well.
</p>
<p class="story">...</p>
</body>
</html>
'''
# 3.创建BeautifulSoup对象
soup = BeautifulSoup(html,'lxml')
# 二、根据属性查找
#查找 id 为 link1 的标签
#方法一：通过命名参数进行查找
a = soup.find(id = 'link1')
print(a)
#方法二：使用attrs来指定属性字典，进行查找
a = soup.find(attrs={'id':'link1'})
print(a)
运行结果
案例代码
# 1.导入模块
from bs4 import BeautifulSoup
# 2.准备文本字符串
html = '''
<title>The Dormouse's story</title>
</head>
<body>
<p class="title">
<b>The Dormouse's story</b>
</p>
<p class="story">Once Upon a time three were three little sister;and their names were
<a href="http://example.com/elsie" class="sister" id="link1">Elsie</a>,
<a href="http://example.com/lacie" class="sister" id="link2">Lacie</a>and
<a href="http://example.com/tillie" class="sister" id="link3">Tillie</a>;
and they lived at the bottom of a well.
</p>
<p class="story">...</p>
</body>
</html>
'''
# 3.创建BeautifulSoup对象
soup = BeautifulSoup(html,'lxml')
#三、根据文本查找
# 获取下面文档中文本为 Elsie 的标签文本
text = soup.find(text='Elsie')
print(text)
运行结果
案例代码
# 1.导入模块
from bs4 import BeautifulSoup
# 2.准备文本字符串
html = '''
<title>The Dormouse's story</title>
</head>
<body>
<p class="title">
<b>The Dormouse's story</b>
</p>
<p class="story">Once Upon a time three were three little sister;and their names were
<a href="http://example.com/elsie" class="sister" id="link1">Elsie</a>,
<a href="http://example.com/lacie" class="sister" id="link2">Lacie</a>and
<a href="http://example.com/tillie" class="sister" id="link3">Tillie</a>;
and they lived at the bottom of a well.
</p>
<p class="story">...</p>
</body>
</html>
'''
# 3.创建BeautifulSoup对象
soup = BeautifulSoup(html,'lxml')
a = soup.find(attrs={'id':'link1'})
#Tag对象
print(type(a)) #<class 'bs4.element.Tag'>
print('标签名：',a.name)
print('标签所有属性:',a.attrs) #输出的class是一个列表，class 一个属性中可以有多个值
print('标签文本内容：',a.text)
运行结果
ctrl+f查找某个类型元素的区域，然后，需找到对应标签的id,然后根据id的值来通过find方法获取文本内容。
案例代码：
# 1.导入相关模块
import requests
from bs4 import BeautifulSoup
# 2.发送请求，获取疫情首页内容
response = requests.get('https://ncov.dxy.cn/ncovh5/view/pneumonia')
home_page = response.content.decode()
#print(home_page)
# 3.使用 BeautifulSoup 获取疫情数据
soup = BeautifulSoup(home_page, 'lxml')
script = soup.find(id='getAreaStat')
text = script.text
print(text)
运行结果：
