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python|通过一个简单爬虫实例简单了解文本解析与读写

python通过request模块可以很简单地通过链接地址获取网络文本。

python的re模板有强大的正则表达式功能来处理文本。

python的文件读写功能也很简单和强大。

1 python通过request模块通过链接地址获取网络文本

1.1 安装request模块

在CMD进入py.exe目录

开始菜单→运行(windows+r)→cmd→通过cd命令进入到python安装目录下的Scripts文件,如:

cd C:\Users\userName\AppData\Local\Programs\Python\Python36-32\Scripts

输入pip install requests

或者 打开Python文件的安装目录,进入Scripts文件中,按住Shift键+鼠标右击,在右键中选择“在此处打开命令窗口”。

或者直接在cmd窗口中输入以下命令:

pip install requests -i http://pypi.douban.com/simple --trusted-host=pypi.douban.com

1.2 通过链接地址获取网络文本

import requests
href = "https://www.3zmm.net/files/article/html/98709/98709808/"
html_response = requests.get(href)
#html_response.encoding = 'utf-8'
html = html_response.text
print(html)           

运行结果:

python|通过一个简单爬虫实例简单了解文本解析与读写

2 建立目录文件

对需要提取网页的链接制作目录文件index.html(可手工也可通过代码提取)。

(为演示需要,截取一部分):

<a href ="https://www.3zmm.net/files/article/html/98709/98709808/13110286.html">第1章 出门即是江湖</a>
<a href ="https://www.3zmm.net/files/article/html/98709/98709808/13110285.html">第2章 麻将出千</a>
<a href ="https://www.3zmm.net/files/article/html/98709/98709808/13110284.html">第3章 移山卸岭</a>
<a href ="https://www.3zmm.net/files/article/html/98709/98709808/13110283.html">第4章 初次试探</a>
<a href ="https://www.3zmm.net/files/article/html/98709/98709808/13110282.html">第5章 炸金花</a>           

当然也可以直接获取网络文本,将通过正则表达式查找建立list。这里为演示需要,建立index.html目录文件。(目录文件可以随时修改,相当于网络截取的目录,演示时更灵活)

3 读取index.html,并建立链接和标题list

import re
with open("index.html",'rU',encoding='utf-8') as strf:
    str = strf.read()
res = r'<a href ="(.*?)">(.*?)</a>' # 使用()分组(分为两组)
indexList = re.findall(res,str)
for link in indexList:
    print('href: ',link[0])
    print('title: ',link[1],'\n')           

运行效果:

python|通过一个简单爬虫实例简单了解文本解析与读写

4 读取index.html中的链接的网络文本

通过链接读取网络文本。

import re
import requests
with open("index.html",'rU',encoding='utf-8') as strf:
    str = strf.read()
res = r'<a href ="(.*?)">(.*?)</a>' # 使用()分组(分为两组)
indexList = re.findall(res,str)
for link in indexList:
    chapter_response = requests.get(link[0])
    #chapter_response.encoding = 'utf-8'
    chapter_html = chapter_response.text
    print(link[1],'\n\n')
    print(chapter_html,'\n\n')           

运行效果:

python|通过一个简单爬虫实例简单了解文本解析与读写

5 文本提取

在网页源文件中提取主体文本。

import re
import requests
with open("index.html",'rU',encoding='utf-8') as strf:
    str = strf.read()
res = r'<a href ="(.*?)">(.*?)</a>' # 使用()分组(分为两组)
indexList = re.findall(res,str)
for link in indexList:
    chapter_response = requests.get(link[0])
    #chapter_response.encoding = 'utf-8'
    chapter_html = chapter_response.text
    chapter_content = re.findall(r'<div id="content" class="showtxt">(.*?)</div>',chapter_html)[0]
    print(link[1],'\n\n')
    print(chapter_content,'\n\n')           

运行效果:

python|通过一个简单爬虫实例简单了解文本解析与读写

6 文本清洗

将不需要的文本替换为空白。

import re
import requests
with open("index.html",'rU',encoding='utf-8') as strf:
    str = strf.read()
res = r'<a href ="(.*?)">(.*?)</a>' # 使用()分组(分为两组)
indexList = re.findall(res,str)
for link in indexList:
    chapter_response = requests.get(link[0])
    #chapter_response.encoding = 'utf-8'
    chapter_html = chapter_response.text
    chapter_content = re.findall(r'<div id="content" class="showtxt">(.*?)</div>',chapter_html)[0]
    str = '<script>chaptererror();</script><br />  请记住本书首发域名:www.3zmm.net。三掌门手机版阅读网址:m.3zmm.net'
    chapter_content = chapter_content.replace(str,'')
    chapter_content = chapter_content.replace(link[0],'')
    print(link[1],'\n\n')
    print(chapter_content,'\n\n')           

运行效果:

python|通过一个简单爬虫实例简单了解文本解析与读写

7 文本处理(文本查找、替换)

import re
import requests
with open("index.html",'rU',encoding='utf-8') as strf:
    str = strf.read()
res = r'<a href ="(.*?)">(.*?)</a>' # 使用()分组(分为两组)
indexList = re.findall(res,str)
for link in indexList:
    chapter_response = requests.get(link[0])
    #chapter_response.encoding = 'utf-8'
    chapter_html = chapter_response.text
    chapter_content = re.findall(r'<div id="content" class="showtxt">(.*?)</div>',chapter_html)[0]
    chapter_content = chapter_content.replace('<script>app2();</script><br />','<p>')
    chapter_content = chapter_content.replace('<br /><br />','</p>\r\n<p>')
    str = '<script>chaptererror();</script><br />  请记住本书首发域名:www.3zmm.net。三掌门手机版阅读网址:m.3zmm.net'
    chapter_content = chapter_content.replace(str,'')
    chapter_content = chapter_content.replace(link[0],'')
    print(link[1],'\n\n')
    print(chapter_content,'\n\n')
    
           

运行效果:

python|通过一个简单爬虫实例简单了解文本解析与读写

8 将文本分别写入文件

import re
import requests

# 1 读取目录文件并提取包含链接和标题的list
with open("index.html",'rU',encoding='utf-8') as strf:
    str = strf.read()
res = r'<a href ="(.*?)">(.*?)</a>' # 使用()分组(分为两组)
indexList = re.findall(res,str)
for link in indexList:
    
# 2 按链接读取网页文本
    chapter_response = requests.get(link[0])
    #chapter_response.encoding = 'utf-8'
    chapter_html = chapter_response.text
    
# 3 提取(截取)文本
    chapter_content = re.findall(r'<div id="content" class="showtxt">(.*?)</div>',chapter_html)[0]
    
# 4 文本清洗(删除不需要文本)
    str = '<script>chaptererror();</script><br />  请记住本书首发域名:www.3zmm.net。三掌门手机版阅读网址:m.3zmm.net'
    chapter_content = chapter_content.replace(str,'')
    chapter_content = chapter_content.replace(link[0],'')
    
# 5 文本处理(查找、替换)

    chapter_content = chapter_content.replace('<script>app2();</script><br />','<p>')
    chapter_content = chapter_content.replace('<br /><br />','</p>\r\n<p>')

    print(link[1],'\n\n')
    # 6 数据持久化(写入到文件)
    fb = open('%s.html'%link[1], 'w', encoding='utf-8');#%s用%link[1]替换
    fb.write(chapter_content)
    fb.close           

9 将文本分别写入文件并适当的添加CSS、JS

import re
import requests
    
# 1 读取目录文件并提取包含链接和标题的list
with open("index.html",'rU',encoding='utf-8') as strf:
    str = strf.read()
res = r'<a href ="(.*?)">(.*?)</a>' # 使用()分组(分为两组)
indexList = re.findall(res,str)
for link in indexList:
    
# 2 按链接读取网页文本
    chapter_response = requests.get(link[0])
    #chapter_response.encoding = 'utf-8'
    chapter_html = chapter_response.text
    
# 3 提取(截取)文本
    chapter_content = re.findall(r'<div id="content" class="showtxt">(.*?)</div>',chapter_html)[0]
    
# 4 文本清洗(删除不需要文本)
    str = '<script>chaptererror();</script><br />  请记住本书首发域名:www.3zmm.net。三掌门手机版阅读网址:m.3zmm.net'
    chapter_content = chapter_content.replace(str,'')
    chapter_content = chapter_content.replace(link[0],'')
    
# 5 文本处理(查找、替换)

    chapter_content = chapter_content.replace('<script>app2();</script><br />','<p>')
    chapter_content = chapter_content.replace('<br /><br />','</p>\r\n<p>')

    print(link[1],'\n\n')
    # 6 数据持久化(写入到文件,并适当添加CSS、JS)
    sn = re.findall(r'第(.*?)章',link[1])[0]
    fb = open('%s.html'%sn, 'w', encoding='utf-8');#%s用%link[1]替换
    
    fheader = open('header.html','r',encoding="UTF-8")
    fb.write(fheader.read())
    fheader.close()

    fb.write('\n<h4>')
    fb.write(sn)

    cha = link[1].replace(sn,'');
    cha = cha.replace('第章 ','')
    fb.write(' ')
    fb.write(cha)
    fb.write('</h4>\n')
    fb.write(chapter_content)

    ffooter = open('footer.html','r',encoding="UTF-8")
    fb.write(ffooter.read())
    ffooter.close()
    fb.close()
           

也可以直接将文件头部、尾部写入文件:

import re
import requests
    
# 1 读取目录文件并提取包含链接和标题的list
with open("index.html",'rU',encoding='utf-8') as strf:
    str = strf.read()
res = r'<a href ="(.*?)">(.*?)</a>' # 使用()分组(分为两组)
indexList = re.findall(res,str)
for link in indexList:
    
# 2 按链接读取网页文本
    chapter_response = requests.get(link[0])
    #chapter_response.encoding = 'utf-8'
    chapter_html = chapter_response.text
    
# 3 提取(截取)文本
    chapter_content = re.findall(r'<div id="content" class="showtxt">(.*?)</div>',chapter_html)[0]
    
# 4 文本清洗(删除不需要文本)
    str = '<script>chaptererror();</script><br />  请记住本书首发域名:www.3zmm.net。三掌门手机版阅读网址:m.3zmm.net'
    chapter_content = chapter_content.replace(str,'')
    chapter_content = chapter_content.replace(link[0],'')
    
# 5 文本处理(查找、替换)

    chapter_content = chapter_content.replace('<script>app2();</script><br />','<p>')
    chapter_content = chapter_content.replace('<br /><br />','</p>\r\n<p>')

    print(link[1],'\n\n')
    # 6 数据持久化(写入到文件,并适当添加CSS、JS)
    sn = re.findall(r'第(.*?)章',link[1])[0]
    fb = open('%s.html'%sn, 'w', encoding='utf-8');#%s用%link[1]替换
    
    # 6.1 写文件头数据
    #fheader = open('header.html','r',encoding="UTF-8")
    #fb.write(fheader.read())
    #fheader.close()
    headertxt = '''
<!DOCTYPE html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title></title>
<link ID="CSS" href="../cssjs/css.css" rel="stylesheet" type="text/css" />
<script charset="utf-8" language="JavaScript" type="text/javascript" src="../cssjs/js.js"></script>
<script>docWrite1();</script>
</head>

<body>
<div id="container">    
    '''
    fb.write(headertxt)
    
    # 6.2 写文件主体
    fb.write('\n<h4>')
    fb.write(sn)

    cha = link[1].replace(sn,'');
    cha = cha.replace('第章 ','')
    fb.write(' ')
    fb.write(cha)
    fb.write('</h4>\n')
    fb.write(chapter_content)
    
    # 6.2 写文件尾部
    #ffooter = open('footer.html','r',encoding="UTF-8")
    #fb.write(ffooter.read())
    #ffooter.close()
    
    footertxt = '''
<div>
<script type=text/javascript>
	docWrite2();
    bootfunc();
    window.onload = myfun;
</script>
</div>

</body>
</html>    
    '''
    fb.write(footertxt)
    fb.close()
              

-End-