Day03:Selenium,BeautifulSoup4

选择器
element: 查找一个
elements: 查找多个

by_id
by_class_name
by_name
by_link_text
by_partial_link_text
by_css_selector

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()

元素交互操作

from selenium import webdriver
from selenium.webdriver import ActionChains
from selenium.webdriver.common.keys import Keys
import time

driver=webdriver.Chrome(r'C:\Users\HP\Desktop\chromedriver.exe')

try:
    driver.implicitly_wait(10)
    driver.get('https://www.jd.com/')
    time.sleep(5)

    input=driver.find_element_by_id('key')
    input.send_keys('围城')

    search=driver.find_element_by_class_name('button')
    search.click()

    time.sleep(3)

    input2=driver.find_element_by_id('key')
    input2.clear()

    time.sleep(1)

    input2.send_keys('墨菲定律')
    input2.send_keys(Keys.ENTER)

    time.sleep(10)

finally:
    driver.close()

```
ActionChains: 动作链
```

from selenium import webdriver
from selenium.webdriver import ActionChains
from selenium.webdriver.common.keys import Keys
import time

driver=webdriver.Chrome(r'C:\Users\HP\Desktop\chromedriver.exe')

try:
    driver.implicitly_wait(10)
    driver.get('https://www.runoob.com/try/try.php?filename=jqueryui-api-droppable')
    time.sleep(5)

    driver.switch_to.frame('iframeResult')
    time.sleep(1)

    source=driver.find_element_by_id('draggable')

    target=driver.find_element_by_id('droppable')

    print(source.size)
    print(source.tag_name)
    print(source.text)
    print(source.location)

    distance=target.location['x']-source.location['x']

    ActionChains(driver).click_and_hold(source).perform()

    s=0
    while s<distance:
        ActionChains(driver).move_by_offset(xoffset=2,yoffset=0).perform()
        s+=2
        time.sleep(0.1)
    ActionChains(driver).release().perform()
    time.sleep(10)

finally:
    driver.close()

```
模拟浏览器的前进后退
```

import time
from selenium import webdriver

browser = webdriver.Chrome()
browser.get('https://www.baidu.com')

browser.get('https://www.taobao.com')

browser.get('http://www.sina.com.cn/')

# 回退
browser.back()

time.sleep(5)

# 前进
browser.forward()

time.sleep(3)

browser.close()

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)
        js_code='''
            window.scrollTo(0,5000)
        '''
        driver.execute_script(js_code)
        time.sleep(5)
        good_list=driver.find_elements_by_class_name('gl-item')
        for good in good_list:
            good_name=good.find_element_by_css_selector('.p-name em').text
            good_url=good.find_element_by_css_selector('.p-name a').get_attribute('href')
            good_price=good.find_element_by_class_name('p-price').text
            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.text','a',encoding='utf-8')as f:
                f.write(good_content)
            num += 1
        print('商品信息写入成功！')
        next_tag=driver.find_elements_by_class_name('pn-next')
        next_tag.click()
        time.sleep(5)
        get_good(driver)
    finally:
        driver.close()

if __name__ == '__main__':
    driver = webdriver.Chrome(r'C:\Users\HP\Desktop\chromedriver.exe')
    try:
        driver.implicitly_wait(10)
        driver.get('http://www.jd.com/')

        input_tag=driver.find_element_by_id('key')
        input_tag.send_keys('墨菲定律')
        input_tag.send_keys(Keys.ENTER)
        get_good(driver)
    finally:
        driver.close()

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)
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)

# bs4类型
print(type(soup))

# 美化功能
html = soup.prettify()
print(html)

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))

# 8、兄弟节点  （sibling: 兄弟姐妹）
print(soup.a)
# 获取下一个兄弟节点
print(soup.a.next_sibling)

# 获取下一个的所有兄弟节点,返回的是一个生成器
print(soup.a.next_siblings)
print(list(soup.a.next_siblings))

# 获取上一个兄弟节点
print(soup.a.previous_sibling)
# 获取上一个的所有兄弟节点，返回的是一个生成器
print(list(soup.a.previous_siblings))

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)

Day03:Selenium,BeautifulSoup4

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