今日内容:
一 Selenium剩余部分
二 BeautifulSoup4
一 Selenium剩余部分
1.元素交互操作:
- 点击、清除
click
clear
- ActionChains
是一个动作链对象，需要把driver驱动传给它。
动作链对象可以操作一系列设定好的动作行为。
- iframe的切换
driver.switch_to.frame('iframeResult')
- 执行js代码
execute_script()
二 BeautifulSoup4
BS4
1.什么BeautifulSoup？
bs4是一个解析库，可以通过某种(解析器)来帮我们提取想要的数据。
2.为什么要使用bs4？
因为它可以通过简洁的语法快速提取用户想要的数据内容。
3.解析器的分类
- lxml
- html.parser
4.安装与使用
- 遍历文档树
- 搜索文档树
补充知识点:
数据格式:
json数据:
{
"name": "tank"
}
XML数据:
<name>tank</name>
HTML:
<html></html>
生成器: yield 值（把值放进生成器中）
def f():
# return 1
yield 1
yield 2
yield 3
g = f()
print(g)
for line in g:
print(line)例1：京东自动清空再搜索
from selenium import webdriver # 用来驱动浏览器的
from selenium.webdriver import ActionChains
from selenium.webdriver.common.keys import Keys
import time
driver = webdriver.Chrome(r'C:\Users\Enz\Desktop\chromedriver.exe')
try:
driver.implicitly_wait(10)
driver.get('https://www.jd.com/')
time.sleep(5)
# 点击、清除
input = driver.find_element_by_id('key')
input.send_keys('围城')
# 通过class查找搜索按钮
search = driver.find_element_by_class_name('button')
search.click() # 点击搜索按钮
time.sleep(3)
input2 = driver.find_element_by_id('key')
input2.clear() # 清空输入框
time.sleep(1)
input2.send_keys('墨菲定律')
input2.send_keys(Keys.ENTER)
time.sleep(10)
finally:
driver.close()例2：滑块移动到指定位置
from selenium import webdriver # 用来驱动浏览器的
from selenium.webdriver import ActionChains
from selenium.webdriver.common.keys import Keys
import time
driver = webdriver.Chrome(r'C:\Users\Enz\Desktop\chromedriver.exe')
try:
driver.implicitly_wait(10)
driver.get('https://www.runoob.com/try/try.php?filename=jqueryui-api-droppable')
time.sleep(5)
# 遗弃方法
# driver.switch_to_frame()
# 新方法
driver.switch_to.frame('iframeResult')
time.sleep(1)
# 起始方块id：draggable
source = driver.find_element_by_id('draggable')
# 目标方块id：droppable
target = driver.find_element_by_id('droppable')
print(source.size) # 大小
print(source.tag_name) # 标签名
print(source.text) #文本
print(source.location) # 坐标：x与y轴
# 找到滑动距离
distance = target.location['x'] - source.location['x']
# 摁住起始滑块
ActionChains(driver).click_and_hold(source).perform()
s = 0;
while s < distance:
# 获取动作链对象
# 每一次位移s距离
ActionChains(driver).move_by_offset(xoffset=2, yoffset=0).perform()
s += 2
time.sleep(0.01)
# 松开起始滑块
ActionChains(driver).release().perform()
time.sleep(10)
finally:
driver.close()例3：执行js代码
from selenium import webdriver
import time
driver = webdriver.Chrome(r'C:\Users\Enz\Desktop\chromedriver.exe')
try:
driver.implicitly_wait(10)
driver.get('https://www.baidu.com/')
driver.execute_script(
'''
alert("Hello Everybody！")
'''
)
time.sleep(10)
finally:
driver.close()例4：模拟浏览器的前进后退
import time
from selenium import webdriver
browser = webdriver.Chrome(r'C:\Users\Enz\Desktop\chromedriver.exe')
browser.get('https://www.baidu.com')
browser.get('https://www.taobao.com')
browser.get('https:/www.sina.com.cn/')
# 回退
browser.back()
time.sleep(5)
# 前进
browser.forward()
time.sleep(3)
browser.close()例5：爬取京东商品信息
import time
from selenium import webdriver
from selenium.webdriver.common.keys import Keys
def get_good(driver):
num = 1
try:
time.sleep(5)
# 下拉滑动5000px
js_code = '''
window.scrollTo(0, 5000)
'''
driver.execute_script(js_code)
# 等待5秒，待商品数据加载
time.sleep(5)
good_list = driver.find_elements_by_class_name('gl-item')
for good in good_list:
# 商品名称
good_name = good.find_element_by_css_selector('.p-name em').text
# 商品链接
good_url = good.find_element_by_css_selector('.p-name a').get_attribute('href')
# 商品价格
good_price = good.find_element_by_class_name('p-price').text
# 商品评价
good_commit = good.find_element_by_class_name('p-commit').text
good_content = f'''
num: {num}
商品名称: {good_name}
商品链接: {good_url}
商品价格: {good_price}
商品评价: {good_commit}
\n
'''
print(good_content)
with open('jd.txt', 'a', encoding='utf-8') as f:
f.write(good_content)
num += 1
print('商品信息写入成功!')
# 找到下一页并点击
next_tag = driver.find_element_by_class_name('pn-next')
next_tag.click()
time.sleep(5)
# 递归调用函数本身
get_good(driver)
finally:
driver.close()
if __name__ == '__main__':
driver = webdriver.Chrome(r'C:\Users\Enz\Desktop\chromedriver.exe')
try:
driver.implicitly_wait(10)
# 往京东发送请求
driver.get('https://www.jd.com/')
# 往京东主页输入框输入墨菲定律，按回车键
input_tag = driver.find_element_by_id('key')
input_tag.send_keys('墨菲定律')
input_tag.send_keys(Keys.ENTER)
# 调用获取商品信息函数
get_good(driver)
finally:
driver.close()
例6：bs4安装与使用
'''
安装解析器：
pip3 install lxml
安装解析库：
pip3 install bs4
'''
html_doc = """
<html><head><title>The Dormouse's story</title></head>
<body>
<p class="sister"><b>$37</b></p>
<p class="story" id="p">Once upon a time there were three little sisters; and their names were
<a href="http://example.com/elsie" class="sister" >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>
"""
from bs4 import BeautifulSoup
# python自带的解析库
# soup = BeautifulSoup(html_doc,'html.parser')
# 调用bs4得到一个soup对象
soup = BeautifulSoup(html_doc,'lxml')
# bs4对象
print(soup)
# bs类型
print(type(soup))
# 美化功能
html = soup.prettify()
print(html)例7：bs4解析库之遍历文档树
html_doc = """
<html><head><title>The Dormouse's story</title></head>
<body>
<p class="sister"><b>$37</b></p>
<p class="story" id="p">Once upon a time there were three little sisters; and their names were
<a href="http://example.com/elsie" class="sister" >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>
"""
from bs4 import BeautifulSoup
soup = BeautifulSoup(html_doc,'lxml')
# print(soup)
# print(type(soup))
# 遍历文档树
# 1。直接使用 *****
print(soup.html)
print(type(soup.html))
print(soup.a)
print(soup.p)
# 2.获取标签的名称
print(soup.a.name)
# 3.获取标签的属性 *****
print(soup.a.attrs) # 获取a标签中所有的属性
print(soup.a.attrs['href'])
# 4.获取标签的文本内容 ******
print(soup.p.text) # $37
# 5.嵌套选择
print(soup.html.body.p)
# 6.子节点、子孙节点
print(soup.p.children) # 返回迭代器对象
print(list(soup.p.children)) # [<b>$37</b>]
# 7.父节点/祖先节点
print(soup.b.parent)
print(soup.b.parents)
print(list(soup.b.parents))例8：bs4之搜索文档树
''''''
'''
find: 找第一个
find_all: 找所有
标签查找与属性查找:
name 属性匹配
name 标签名
attrs 属性查找匹配
text 文本匹配
标签:
- 字符串过滤器
字符串全局匹配
- 正则过滤器
re模块匹配
- 列表过滤器
列表内的数据匹配
- bool过滤器
True匹配
- 方法过滤器
用于一些要的属性以及不需要的属性查找。
属性:
- class_
- id
'''
html_doc = """
<html><head><title>The Dormouse's story</title></head><body><p class="sister"><b>$37</b></p><p class="story" id="p">Once upon a time there were three little sisters; and their names were<a href="http://example.com/elsie" class="sister" >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>
"""
from bs4 import BeautifulSoup
soup = BeautifulSoup(html_doc, 'lxml')
# name 标签名
# attrs 属性查找匹配
# text 文本匹配
# find与find_all搜索文档
'''
字符串过滤器
'''
p = soup.find(name='p')
p_s = soup.find_all(name='p')
print(p)
print(p_s)
# name + attrs
p = soup.find(name='p', attrs={"id": "p"})
print(p)
# name + text
tag = soup.find(name='title', text="The Dormouse's story")
print(tag)
# name + attrs + text
tag = soup.find(name='a', attrs={"class": "sister"}, text="Elsie")
print(tag)
'''
- 正则过滤器
re模块匹配
'''
import re
# name
# 根据re模块匹配带有a的节点
a = soup.find(name=re.compile('a'))
print(a)
a_s = soup.find_all(name=re.compile('a'))
print(a_s)
# attrs
a = soup.find(attrs={"id": re.compile('link')})
print(a)
# - 列表过滤器
# 列表内的数据匹配
print(soup.find(name=['a', 'p', 'html', re.compile('a')]))
print(soup.find_all(name=['a', 'p', 'html', re.compile('a')]))
# - bool过滤器
# True匹配
print(soup.find(name=True, attrs={"id": True}))
# - 方法过滤器
# 用于一些要的属性以及不需要的属性查找。
def have_id_not_class(tag):
# print(tag.name)
if tag.name == 'p' and tag.has_attr("id") and not tag.has_attr("class"):
return tag
# print(soup.find_all(name=函数对象))
print(soup.find_all(name=have_id_not_class))
# 补充知识点:
# id
a = soup.find(id='link2')
print(a)
# class
p = soup.find(class_='sister')
print(p)
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