标签：rac dso data .text poi bottom http请求 递归 user
网络爬虫（又被称为网页蜘蛛，网络机器人，在FOAF社区中间，更经常的称为网页追逐者），是一种按照一定的规则，自动地抓取万维网信息的程序或者脚本。另外一些不常使用的名字还有蚂蚁、自动索引、模拟程序或者蠕虫。
Python标准库中提供了：urllib、urllib2、httplib等模块以供Http请求，但是，它的 API 太渣了。它是为另一个时代、另一个互联网所创建的。它需要巨量的工作，甚至包括各种方法覆盖，来完成最简单的任务。
Requests 是使用 Apache2 Licensed 许可证的 基于Python开发的HTTP 库，其在Python内置模块的基础上进行了高度的封装，从而使得Pythoner进行网络请求时，变得美好了许多，使用Requests可以轻而易举的完成浏览器可有的任何操作。
1、GET请求
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# 1、无参数实例import requestsret = requests.get(‘https://github.com/timeline.json‘)print ret.urlprint ret.text# 2、有参数实例import requestspayload = {‘key1‘: ‘value1‘, ‘key2‘: ‘value2‘}ret = requests.get("http://httpbin.org/get", params=payload)print ret.urlprint ret.text |
向 https://github.com/timeline.json 发送一个GET请求，将请求和响应相关均封装在 ret 对象中。
2、POST请求
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# 1、基本POST实例import requestspayload = {‘key1‘: ‘value1‘, ‘key2‘: ‘value2‘}ret = requests.post("http://httpbin.org/post", data=payload)print ret.text# 2、发送请求头和数据实例import requestsimport jsonurl = ‘https://api.github.com/some/endpoint‘payload = {‘some‘: ‘data‘}headers = {‘content-type‘: ‘application/json‘}ret = requests.post(url, data=json.dumps(payload), headers=headers)print ret.textprint ret.cookies |
向https://api.github.com/some/endpoint发送一个POST请求，将请求和相应相关的内容封装在 ret 对象中。
3、其他请求
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requests.get(url, params=None, **kwargs)requests.post(url, data=None, json=None, **kwargs)requests.put(url, data=None, **kwargs)requests.head(url, **kwargs)requests.delete(url, **kwargs)requests.patch(url, data=None, **kwargs)requests.options(url, **kwargs)# 以上方法均是在此方法的基础上构建requests.request(method, url, **kwargs) |
requests模块已经将常用的Http请求方法为用户封装完成，用户直接调用其提供的相应方法即可
官方文档：http://cn.python-requests.org/zh_CN/latest/user/quickstart.html#id4
BeautifulSoup是一个模块，该模块用于接收一个HTML或XML字符串，然后将其进行格式化，之后遍可以使用他提供的方法进行快速查找指定元素，从而使得在HTML或XML中查找指定元素变得简单。
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from bs4 import BeautifulSouphtml_doc = """<html><head><title>The Dormouse‘s story</title></head><body>asdf <div class="title"> <b>The Dormouse‘s story总共</b> <h1>f</h1> </div><div class="story">Once upon a time there were three little sisters; and their names were <a class="sister0" id="link1">Els<span>f</span>ie</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.</div>ad<br/>sf<p class="story">...</p></body></html>"""soup = BeautifulSoup(html_doc, features="lxml")# 找到第一个a标签tag1 = soup.find(name=‘a‘)# 找到所有的a标签tag2 = soup.find_all(name=‘a‘)# 找到id＝link2的标签tag3 = soup.select(‘#link2‘) |
安装：
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pip3 install beautifulsoup4 |
使用示例：
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from bs4 import BeautifulSouphtml_doc = """<html><head><title>The Dormouse‘s story</title></head><body> ...</body></html>"""soup = BeautifulSoup(html_doc, features="lxml") |
1. name，标签名称
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# tag = soup.find(‘a‘)# name = tag.name # 获取# print(name)# tag.name = ‘span‘ # 设置# print(soup) |
2. attr，标签属性
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# tag = soup.find(‘a‘)# attrs = tag.attrs # 获取# print(attrs)# tag.attrs = {‘ik‘:123} # 设置# tag.attrs[‘id‘] = ‘iiiii‘ # 设置# print(soup) |
3. children,所有子标签
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# body = soup.find(‘body‘)# v = body.children |
4. children,所有子子孙孙标签
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# body = soup.find(‘body‘)# v = body.descendants |
5. clear,将标签的所有子标签全部清空（保留标签名）
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# tag = soup.find(‘body‘)# tag.clear()# print(soup) |
6. decompose,递归的删除所有的标签
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# body = soup.find(‘body‘)# body.decompose()# print(soup) |
7. extract,递归的删除所有的标签，并获取删除的标签
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# body = soup.find(‘body‘)# v = body.extract()# print(soup) |
8. decode,转换为字符串（含当前标签）；decode_contents（不含当前标签）
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# body = soup.find(‘body‘)# v = body.decode()# v = body.decode_contents()# print(v) |
9. encode,转换为字节（含当前标签）；encode_contents（不含当前标签）
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# body = soup.find(‘body‘)# v = body.encode()# v = body.encode_contents()# print(v) |
10. find,获取匹配的第一个标签
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# tag = soup.find(‘a‘)# print(tag)# tag = soup.find(name=‘a‘, attrs={‘class‘: ‘sister‘}, recursive=True, text=‘Lacie‘)# tag = soup.find(name=‘a‘, class_=‘sister‘, recursive=True, text=‘Lacie‘)# print(tag) |
11. find_all,获取匹配的所有标签
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# tags = soup.find_all(‘a‘)# print(tags)# tags = soup.find_all(‘a‘,limit=1)# print(tags)# tags = soup.find_all(name=‘a‘, attrs={‘class‘: ‘sister‘}, recursive=True, text=‘Lacie‘)# # tags = soup.find(name=‘a‘, class_=‘sister‘, recursive=True, text=‘Lacie‘)# print(tags)# ####### 列表 ######## v = soup.find_all(name=[‘a‘,‘div‘])# print(v)# v = soup.find_all(class_=[‘sister0‘, ‘sister‘])# print(v)# v = soup.find_all(text=[‘Tillie‘])# print(v, type(v[0]))# v = soup.find_all(id=[‘link1‘,‘link2‘])# print(v)# v = soup.find_all(href=[‘link1‘,‘link2‘])# print(v)# ####### 正则 #######import re# rep = re.compile(‘p‘)# rep = re.compile(‘^p‘)# v = soup.find_all(name=rep)# print(v)# rep = re.compile(‘sister.*‘)# v = soup.find_all(class_=rep)# print(v)# rep = re.compile(‘http://www.oldboy.com/static/.*‘)# v = soup.find_all(href=rep)# print(v)# ####### 方法筛选 ######## def func(tag):# return tag.has_attr(‘class‘) and tag.has_attr(‘id‘)# v = soup.find_all(name=func)# print(v)# ## get,获取标签属性# tag = soup.find(‘a‘)# v = tag.get(‘id‘)# print(v) |
12. has_attr,检查标签是否具有该属性
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# tag = soup.find(‘a‘)# v = tag.has_attr(‘id‘)# print(v) |
13. get_text,获取标签内部文本内容
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# tag = soup.find(‘a‘)# v = tag.get_text(‘id‘)# print(v) |
14. index,检查标签在某标签中的索引位置
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# tag = soup.find(‘body‘)# v = tag.index(tag.find(‘div‘))# print(v)# tag = soup.find(‘body‘)# for i,v in enumerate(tag):# print(i,v) |
15. is_empty_element,是否是空标签(是否可以是空)或者自闭合标签，
判断是否是如下标签：‘br‘ , ‘hr‘, ‘input‘, ‘img‘, ‘meta‘,‘spacer‘, ‘link‘, ‘frame‘, ‘base‘
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# tag = soup.find(‘br‘)# v = tag.is_empty_element# print(v) |
16. 当前的关联标签
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# soup.next# soup.next_element# soup.next_elements# soup.next_sibling# soup.next_siblings## tag.previous# tag.previous_element# tag.previous_elements# tag.previous_sibling# tag.previous_siblings## tag.parent# tag.parents |
17. 查找某标签的关联标签
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# tag.find_next(...)# tag.find_all_next(...)# tag.find_next_sibling(...)# tag.find_next_siblings(...)# tag.find_previous(...)# tag.find_all_previous(...)# tag.find_previous_sibling(...)# tag.find_previous_siblings(...)# tag.find_parent(...)# tag.find_parents(...)# 参数同find_all |
18. select,select_one, CSS选择器
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soup.select("title")soup.select("p nth-of-type(3)")soup.select("body a")soup.select("html head title")tag = soup.select("span,a")soup.select("head > title")soup.select("p > a")soup.select("p > a:nth-of-type(2)")soup.select("p > #link1")soup.select("body > a")soup.select("#link1 ~ .sister")soup.select("#link1 + .sister")soup.select(".sister")soup.select("[class~=sister]")soup.select("#link1")soup.select("a#link2")soup.select(‘a[href]‘)soup.select(‘a[href="http://example.com/elsie"]‘)soup.select(‘a[href^="http://example.com/"]‘)soup.select(‘a[href$="tillie"]‘)soup.select(‘a[href*=".com/el"]‘)from bs4.element import Tagdef default_candidate_generator(tag): for child in tag.descendants: if not isinstance(child, Tag): continue if not child.has_attr(‘href‘): continue yield childtags = soup.find(‘body‘).select("a", _candidate_generator=default_candidate_generator)print(type(tags), tags)from bs4.element import Tagdef default_candidate_generator(tag): for child in tag.descendants: if not isinstance(child, Tag): continue if not child.has_attr(‘href‘): continue yield childtags = soup.find(‘body‘).select("a", _candidate_generator=default_candidate_generator, limit=1)print(type(tags), tags) |
19. 标签的内容
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# tag = soup.find(‘span‘)# print(tag.string) # 获取# tag.string = ‘new content‘ # 设置# print(soup)# tag = soup.find(‘body‘)# print(tag.string)# tag.string = ‘xxx‘# print(soup)# tag = soup.find(‘body‘)# v = tag.stripped_strings # 递归内部获取所有标签的文本# print(v) |
20.append在当前标签内部追加一个标签
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# tag = soup.find(‘body‘)# tag.append(soup.find(‘a‘))# print(soup)## from bs4.element import Tag# obj = Tag(name=‘i‘,attrs={‘id‘: ‘it‘})# obj.string = ‘我是一个新来的‘# tag = soup.find(‘body‘)# tag.append(obj)# print(soup) |
21.insert在当前标签内部指定位置插入一个标签
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# from bs4.element import Tag# obj = Tag(name=‘i‘, attrs={‘id‘: ‘it‘})# obj.string = ‘我是一个新来的‘# tag = soup.find(‘body‘)# tag.insert(2, obj)# print(soup) |
22. insert_after,insert_before 在当前标签后面或前面插入
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# from bs4.element import Tag# obj = Tag(name=‘i‘, attrs={‘id‘: ‘it‘})# obj.string = ‘我是一个新来的‘# tag = soup.find(‘body‘)# # tag.insert_before(obj)# tag.insert_after(obj)# print(soup) |
23. replace_with 在当前标签替换为指定标签
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# from bs4.element import Tag# obj = Tag(name=‘i‘, attrs={‘id‘: ‘it‘})# obj.string = ‘我是一个新来的‘# tag = soup.find(‘div‘)# tag.replace_with(obj)# print(soup) |
24. 创建标签之间的关系
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# tag = soup.find(‘div‘)# a = soup.find(‘a‘)# tag.setup(previous_sibling=a)# print(tag.previous_sibling) |
25. wrap，将指定标签把当前标签包裹起来
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# from bs4.element import Tag# obj1 = Tag(name=‘div‘, attrs={‘id‘: ‘it‘})# obj1.string = ‘我是一个新来的‘## tag = soup.find(‘a‘)# v = tag.wrap(obj1)# print(soup)# tag = soup.find(‘a‘)# v = tag.wrap(soup.find(‘p‘))# print(soup) |
26. unwrap，去掉当前标签，将保留其包裹的标签
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# tag = soup.find(‘a‘)# v = tag.unwrap()# print(soup) |
更多参数官方：http://beautifulsoup.readthedocs.io/zh_CN/v4.4.0/
标签：rac dso data .text poi bottom http请求 递归 user
原文地址：https://www.cnblogs.com/superfangchao/p/9345994.html
