python爬虫Day 03
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()
元素交互操作
'''''' ''' 点击、清除 ''' # from selenium import webdriver # from selenium.webdriver import ActionChains # from selenium.webdriver.common.keys import Keys # 键盘按键操作 # import time # # # # driver = webdriver.Chrome() # # 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() ''' ActionChains: 动作链 ''' # from selenium import webdriver # from selenium.webdriver import ActionChains # from selenium.webdriver.common.keys import Keys # 键盘按键操作 # import time # # # # driver = webdriver.Chrome() # try: # driver.implicitly_wait(10) # driver.get('http://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) # # # 获取动作链对象 # action = ActionChains(driver) # # # 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') # # # 方式一: 秒移 # # 起始方块瞬间移动到目标方块中 # # 拟定好一个动作，需要调用执行方法perform # # action.drag_and_drop(source, target).perform() # # # time.sleep(10) # # finally: # driver.close() # from selenium import webdriver # from selenium.webdriver import ActionChains # from selenium.webdriver.common.keys import Keys # 键盘按键操作 # import time # # driver = webdriver.Chrome() # try: # driver.implicitly_wait(10) # driver.get('http://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() # # # 方式二: 一点一点移动 # 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(0.1) # # # 松开起始滑块 # ActionChains(driver).release().perform() # # # time.sleep(10) # # finally: # driver.close() ''' 执行js代码 ''' from selenium import webdriver import time driver = webdriver.Chrome() try: driver.implicitly_wait(10) driver.get('https://www.baidu.com/') driver.execute_script( ''' alert("浙江大学，是浙江最好的大学！") ''' ) time.sleep(10) finally: driver.close()
其他操作
'''''' ''' 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
# '''''' # ''' # 初级版: # from tank! # ''' # import time # from selenium import webdriver # from selenium.webdriver.common.keys import Keys # # driver = webdriver.Chrome() # # num = 1 # # 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) # # time.sleep(5) # # # good_list = driver.find_elements_by_class_name('gl-item') # for good in good_list: # # print(good) # # 商品名称 # good_name = good.find_element_by_css_selector('.p-name em').text # # print(good_name) # # # 商品链接 # good_url = good.find_element_by_css_selector('.p-name a').get_attribute('href') # # print(good_url) # # # 商品价格 # good_price = good.find_element_by_class_name('p-price').text # # print(good_price) # # # 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!') # # # finally: # driver.close() '''''' ''' 中级版 ''' # import time # from selenium import webdriver # from selenium.webdriver.common.keys import Keys # # driver = webdriver.Chrome() # # num = 1 # # 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) # # 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: # # print(good) # # 商品名称 # good_name = good.find_element_by_css_selector('.p-name em').text # # print(good_name) # # # 商品链接 # good_url = good.find_element_by_css_selector('.p-name a').get_attribute('href') # # print(good_url) # # # 商品价格 # good_price = good.find_element_by_class_name('p-price').text # # print(good_price) # # # 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(10) # # finally: # driver.close() ''' 狂暴版 ''' 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() 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()
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)
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