一、Beautifu Soup库

from bs4 import BeautifulSoup

soup = BeautifulSoup(demo,"html.parser")

Tag、Name、Attributes、NavigableString、Comment

.contents 子节点的列表，将<tag>所有儿子节点存入列表

.children 子节点的迭代类型

.descendants 子孙节点的迭代类型

.parent 节点的父亲标签

.parents 节点先辈标签的迭代类型

.next_sibling(s) 返回安照HTML文本顺序的下一个平行节点标签

.previous_sibling(s) 上一个

>>> import requests

>>> r = requests.get("http://python123.io/ws/demo.html")

>>> demo = r.text

>>> demo

'<html><head><title>This is a python demo page</title></head>\r\n<body>\r\n<p class="title"><b>The demo python introduces several python courses.</b></p>\r\n<p class="course">Python is a wonderful general-purpose programming language. You can learn Python from novice to professional by tracking the following courses:\r\n<a href="http://www.icourse163.org/course/BIT-268001" class="py1" id="link1">Basic Python</a> and <a href="http://www.icourse163.org/course/BIT-1001870001" class="py2" id="link2">Advanced Python</a>.</p>\r\n</body></html>'

>>>from bs4 import BeautifulSoup

>>> soup = BeautifulSoup(demo,"html.parser")
>>> soup.prettify()
'<html>\n <head>\n <title>\n This is a python demo page\n </title>\n </head>\n <body>\n <p class="title">\n <b>\n The demo python introduces several python courses.\n </b>\n </p>\n <p class="course">\n Python is a wonderful general-purpose programming language. You can learn Python from novice to professional by tracking the following courses:\n <a class="py1" href="http://www.icourse163.org/course/BIT-268001" id="link1">\n Basic Python\n </a>\n and\n <a class="py2" href="http://www.icourse163.org/course/BIT-1001870001" id="link2">\n Advanced Python\n </a>\n .\n </p>\n </body>\n</html>'
>>> print(soup.prettify())
<html>
<head>
<title>
This is a python demo page
</title>
</head>
<body>
<p class="title">
<b>
The demo python introduces several python courses.
</b>
</p>
<p class="course">
Python is a wonderful general-purpose programming language. You can learn Python from novice to professional by tracking the following courses:
<a class="py1" href="http://www.icourse163.org/course/BIT-268001" id="link1">
Basic Python
</a>
and
<a class="py2" href="http://www.icourse163.org/course/BIT-1001870001" id="link2">
Advanced Python
</a>
.
</p>
</body>
</html>

二、信息组织与提取

1.信息标记的三种形式：

XML：尖括号

JSON：有类型键值对

YAML：无类型

3.信息提取的一般方法

（1）完整解析信息地标记形式，再提取关键信息

（2）无视标记形式，直接搜索关键信息

（3）融合方法

实例：

>>>  import requests

 r = requests.get("http://python123.io/ws/demo.html")

 demo = r.text

 demo

SyntaxError: unexpected indent

>>> import requests

>>> r = requests.get("http://python123.io/ws/demo.html")

>>> demo = r.text

>>> demo

'<html><head><title>This is a python demo page</title></head>\r\n<body>\r\n<p class="title"><b>The demo python introduces several python courses.</b></p>\r\n<p class="course">Python is a wonderful general-purpose programming language. You can learn Python from novice to professional by tracking the following courses:\r\n<a href="http://www.icourse163.org/course/BIT-268001" class="py1" id="link1">Basic Python</a> and <a href="http://www.icourse163.org/course/BIT-1001870001" class="py2" id="link2">Advanced Python</a>.</p>\r\n</body></html>'

>>> from bs4 import BeautifulSoup

>>> soup = BeautifulSoup(demo,"html,parser")

Traceback (most recent call last):

  File "<pyshell#6>", line 1, in <module>

    soup = BeautifulSoup(demo,"html,parser")

  File "C:\Users\ASUS\AppData\Local\Programs\Python\Python37-32\lib\site-packages\bs4\__init__.py", line 196, in __init__

    % ",".join(features))

bs4.FeatureNotFound: Couldn't find a tree builder with the features you requested: html,parser. Do you need to install a parser library?

>>> yes

Traceback (most recent call last):

  File "<pyshell#7>", line 1, in <module>

    yes

NameError: name 'yes' is not defined

>>> soup = BeautifulSoup(demo,"html.parser")

>>> from link in soup.find_all('a')

SyntaxError: invalid syntax

>>> for link in soup.find_all('a')

SyntaxError: invalid syntax

>>> for link in soup.find_all('a'):

    print(link.get('href'))

http://www.icourse163.org/course/BIT-268001

http://www.icourse163.org/course/BIT-1001870001

4.基于bs4库的HTML内容查找方法

<>.find_all(name,attrs,recursive,string,**kwargs)

返回一个列表类型，存储查找的结果

name：对标签名称的检索字符串

>>> soup.find_all('a')

[<a class="py1" href="http://www.icourse163.org/course/BIT-268001" id="link1">Basic Python</a>, <a class="py2" href="http://www.icourse163.org/course/BIT-1001870001" id="link2">Advanced Python</a>]

>>> soup.find_all(['a','b'])

[<b>The demo python introduces several python courses.</b>, <a class="py1" href="http://www.icourse163.org/course/BIT-268001" id="link1">Basic Python</a>, <a class="py2" href="http://www.icourse163.org/course/BIT-1001870001" id="link2">Advanced Python</a>]

>>> for tag in soup.find_all(True):

    print(tag.name)

html

head

title

body

p

b

p

a

a

>>> import re

>>> for tag in soup.find_all(re.compile('b')):

    print(tag.name)

body

b

attrs：对标签属性值的检索字符串，可标注属性检索

>>> soup.find_all('p','course')

[<p class="course">Python is a wonderful general-purpose programming language. You can learn Python from novice to professional by tracking the following courses:

<a class="py1" href="http://www.icourse163.org/course/BIT-268001" id="link1">Basic Python</a> and <a class="py2" href="http://www.icourse163.org/course/BIT-1001870001" id="link2">Advanced Python</a>.</p>]

>>> soup.find_all(id='link1')

[<a class="py1" href="http://www.icourse163.org/course/BIT-268001" id="link1">Basic Python</a>]

>>> soup.find_all(id=re.compile('link'))

[<a class="py1" href="http://www.icourse163.org/course/BIT-268001" id="link1">Basic Python</a>, <a class="py2" href="http://www.icourse163.org/course/BIT-1001870001" id="link2">Advanced Python</a>]

recursive：是否对子孙全部检索，默认True

>>> soup.find_all('a',recursive=False)

[]

string：<>...</>中字符串区域的检索字符串

>>> soup.find_all(string = 'Basic Python')

['Basic Python']

>>> soup.find_all(string = re.compile("python"))

['This is a python demo page', 'The demo python introduces several python courses.']

>>> soup(string = 'Basic Python')
['Basic Python']

扩展方法：

<>.find() find_parents parent next_sibling(s) previous_sibling(s)

三、中国大学排名定向爬虫

技术路线：requests+bs4

可行性：robots协议

步骤1：获取内容 getHTMLText()

2：数据结构 fillUnivList()

3：利用DS printUnivList()

import requests

from bs4 import BeautifulSoup

import bs4

def getHTMLText(url):

    try:

        r = requests.get(url,timeout=30)

        r.raise_for_status()

        r.encoding = r.apparent_encoding

        return r.text

    except:

        return ""

def fillUnivList(ulist,html):

    soup = BeautifulSoup(html,'html.parser')

    for tr in soup.find('tbody').children:

        if isinstance(tr,bs4.element.Tag):#过滤

            tds = tr('td')

            ulist.append([tds[0].string,tds[1].string,tds[3].string])

def printUnivList(ulist,num):

    #tplt = "{0:^10}\t{1:{3}^10}\t{2:^10}"

    print("{:^10}\t{:^6}\t{:^10}".format("排名","学校名称","总分"))

    for i in range(num):

        u = ulist[i]

        print("{:^10}\t{:^6}\t{:^10}".format(u[0],u[1],u[2]))

def main():

    uinfo = []

    url='http://www.zuihaodaxue.com/zuihaodaxuepaiming2019.html'

    html = getHTMLText(url)

    fillUnivList(uinfo,html)

    printUnivList(uinfo,20)

main()

优化后：

import requests

from bs4 import BeautifulSoup

import bs4

def getHTMLText(url):

    try:

        r = requests.get(url,timeout=30)

        r.raise_for_status()

        r.encoding = r.apparent_encoding

        return r.text

    except:

        return ""

def fillUnivList(ulist,html):

    soup = BeautifulSoup(html,'html.parser')

    for tr in soup.find('tbody').children:

        if isinstance(tr,bs4.element.Tag):#过滤

            tds = tr('td')

            ulist.append([tds[0].string,tds[1].string,tds[3].string])

def printUnivList(ulist,num):

    tplt = "{0:^10}\t{1:{3}^10}\t{2:^10}"

    print(tplt.format("排名","学校名称","总分",chr(12288)))

    for i in range(num):

        u = ulist[i]

        print(tplt.format(u[0],u[1],u[2],chr(12288)))

def main():

    uinfo = []

    url='http://www.zuihaodaxue.com/zuihaodaxuepaiming2019.html'

    html = getHTMLText(url)

    fillUnivList(uinfo,html)

    printUnivList(uinfo,20)

main()

The website is API（2）的更多相关文章

  1. The website is API（3）

    网络爬虫实战知识准备: Requests库.robots(网络爬虫排除标准).BeautifulSoup库 一.Re正则表达式 1. 简洁地表达一组字符串 通用的字符串表达框架 字符串匹配 编译: 2 ...

  2. The website is API（1）

    Requests 自动爬取HTML页面 自动网路请求提交 robots 网络爬虫排除标准 Beautiful Soup 解析HTML页面 实战 Re 正则表达式详解提取页面关键信息 Scrapy*框架 ...

  3. The website is API（4）

    1.淘宝商品信息定向爬虫 目标:获取淘宝搜索页面信息,提取其中的商品名称和价格 理解:淘宝的搜索接口 翻页的处理 技术路线:requests+re https://s.taobao.com/searc ...

  4. 我这么玩Web Api（二）：数据验证，全局数据验证与单元测试

    目录 一.模型状态 - ModelState 二.数据注解 - Data Annotations 三.自定义数据注解 四.全局数据验证 五.单元测试   一.模型状态 - ModelState 我理解 ...

  5. [Android]使用Dagger 2依赖注入 - API（翻译）

    以下内容为原创,欢迎转载,转载请注明 来自天天博客:http://www.cnblogs.com/tiantianbyconan/p/5092525.html 使用Dagger 2依赖注入 - API ...

  6. [转]ASP.NET Web API（三）：安全验证之使用摘要认证(digest authentication)

    本文转自:http://www.cnblogs.com/parry/p/ASPNET_MVC_Web_API_digest_authentication.html 在前一篇文章中,主要讨论了使用HTT ...

  7. ASP.NET Web API（三）：安全验证之使用摘要认证(digest authentication)

    在前一篇文章中,主要讨论了使用HTTP基本认证的方法,因为HTTP基本认证的方式决定了它在安全性方面存在很大的问题,所以接下来看看另一种验证的方式:digest authentication,即摘要认 ...

  8. ASP.NET Web API（二）：安全验证之使用HTTP基本认证

    在前一篇文章ASP.NET Web API(一):使用初探,GET和POST数据中,我们初步接触了微软的REST API: Web API. 我们在接触了Web API的后就立马发现了有安全验证的需求 ...

  9. 微信公众平台Js API（WeixinApi）

    微信公众平台Js API(WeixinApi): https://github.com/zxlie/WeixinApi#user-content-3%E9%9A%90%E8%97%8F%E5%BA%9 ...

随机推荐

  1. 留学生如何在Presentation中拿高分？

    掐指一算,留学生们最近应该马上遇到Presentation任务.一般来说,这类的任务会占最终成绩的20-30%,对于期末成绩有一定的影响,如果想拿高分,就需要好好的准备. 所以本文算是系列里的第一篇( ...

  2. 关于torch.norm函数的笔记

    先看一下它的参数: norm(p='fro', dim=None, keepdim=False, dtype=None) p: the order of norm. 一般来说指定 $p = 1, 2$ ...

  3. Spring AOP复习

    最近在翻<Spring In Action>Spring 实战这本书,重新了解了一下AOP的概念和思想并写了一个小Demo示例,记录在这里: 环境:intelliJ IDEA 2018.M ...

  4. Python多线程,线程死锁及解决,生产者与消费者问题

    1.Thread类 普通调用 t = Thread(target=test, args=(i,)) # test为目标函数名, 若函数需要参数将其以元组形 # 式赋给args, 若无参数可不写 t.s ...

  5. UVA - 10118 Free Candies(免费糖果)(dp---记忆化搜索)

    题意:桌上有4堆糖果,每堆有N(N<=40)颗.佳佳有一个最多可以装5颗糖的小篮子.他每次选择一堆糖果,把最顶上的一颗拿到篮子里.如果篮子里有两颗颜色相同的糖果,佳佳就把它们从篮子里拿出来放到自 ...

  6. HDU 5428：The Factor

    The Factor  Accepts: 101  Submissions: 811  Time Limit: 2000/1000 MS (Java/Others)  Memory Limit: 65 ...

  7. pytorch安装及基本用法

    20180425更新  安装pytorch0.4.0: conda uninstall pytorch # 如果是CUDA版本的话 conda uninstall cuda80 cuda90 # 如果 ...

  8. RK3399开发板Android镜像烧写之Windows系统映像烧写

    4.1.1 l RKTool  驱动安装(基于迅为iTOP-3399开发板)DriverAssitant_v4.5.zip 文件,打开 驱动安装成功,如下图: 注意事项:1.目前支持的操作系统包括:X ...

  9. 实验吧web-易-Forms

    打开网页,查看源码, 第二行,showsource的value是0,我们在查看器中将showsource的value值改为1,然后随便输入一个数,可以看到页面出现 意思就是我们输入的PIN的值应该是代 ...

  10. (转)out.writer和out.print

    JSP中out.write()和out.print()的区别 out对象的类型是JspWriter.JspWriter继承了java.io.Writer类. 1)print方法是子类JspWriter ...