爬虫实例--菜鸟教程_爬虫菜鸟教程

1、第一种方法

# 第一种方式：requests 和 lxml结合使用
import requests
from lxml import etree
#1、拿到所有的页面链接，并使用yield返回完整的超链接
def get_html(url):
#     获取页面HTML
    html=requests.get(url)
#     使用etree格式化HTML
    seq=etree.HTML(html.text)
    link_list=seq.xpath('//*[@id="content"]/ul/li/a/@href')
    for i in link_list:
        yield "http://www.runoob.com"+i       
# 2、获取详细的页面数据
def get_html_link(link):
    for i in link:
#         获取界面
        link_html=requests.get(i)
#     初始化
        link_seq=etree.HTML(link_html.content)
#     得到标题
        title=link_seq.xpath('//*[@id="content"]/h1/text()')[0]
#     得到题目内容
        subject=link_seq.xpath('//*[@id="content"]/p[position()>1 and position()<4]/text()')
        subject_list='\n'.join(subject)
        yield (title,subject_list) 
# 3、保存数据
def save_subject(title_subject):
    with open("G:/1.txt",'a+',encoding='utf-8') as f:
        for title,subject_list in title_subject:
            f.write(title+'\n')
            f.write(subject_list+'\n')
            f.write("#"*50+'\n')
# 4、函数回调
def funcall(url):
    link=get_html(url)
    title_subject=get_html_link(link)
    save_subject(title_subject)
# 5、主函数
def main():
    url='http://www.runoob.com/python/python-100-examples.html'
    funcall(url)
if __name__=="__main__":
    main()
 
# for i in get_html('http://www.runoob.com/python/python-100-examples.html'):
#     print(i)
# for i in get_html_link(link):
#     print(i)

2、第二种方法

# 第二种方式：urllib.request 与 beautifulsoup结合使用
import urllib.request
from bs4 import BeautifulSoup
# 1、获取所有页面链接
def get_html(url):
#     获取页面HTML源码
    html=urllib.request.urlopen(url).read()
#     格式化html
    soup=BeautifulSoup(html,'lxml')
#     首先找到第一个id='content'的标签，并找到子标签ul(2个)
#     其次遍历子标签ul,并获取到所有的ul的子标签li
#     然后遍历li标签，并获取到li标签下的所有a标签
#     使用yield返回超链接
    for i in soup.find(id='content').find_all('ul'):
        for j in i.find_all('li'):
            for k in j.find_all('a'):
                yield 'http://www.runoob.com'+k['href']       
# 2、获取详细的页面数据
def get_html_link(link):
#     遍历所有的超链接
    for i in link:
#         请求超链接页面HTML
        link_list=urllib.request.urlopen(i).read()
#     格式化HTML
        soup=BeautifulSoup(link_list,'lxml')
#     获取id='content'的标签
        content=soup.find(id='content')
        if content:
#             获取h1标签的内容
            title=content.find('h1').string
#     获取前3个p标签的内容
            conten_list=content.find_all('p',limit=3)
            subject=''
            for j in conten_list:
                subject+=j.get_text()
            yield (title,subject)
# 3、数据保存
def save_suject(title_content):
    with open('G:/2.txt','w+',encoding='utf+8') as f:
        for tile,content in title_content:
            f.write(tile+'\n')
            f.write(content+'\n')    
            f.write('#'*80+'\n')
# 4、函数回调
def fun_call(url):
    link=get_html(url)
    title_content=get_html_link(link)
    save_suject(title_content)
# 5、主函数
def main():
    url='http://www.runoob.com/python/python-100-examples.html'
    fun_call(url)
if __name__=='__main__':
    main()

3、第三种方法

# 第三种方式
import requests,re
from bs4 import BeautifulSoup
# 1、获取页面的超链接信息
def get_html(url):
    html=requests.get(url)
    html.encoding='utf-8'
    soup=BeautifulSoup(html.text,'lxml')
    for i in soup.find_all('a',href=re.compile('^/python/python-exercise')):
        yield 'http://www.runoob.com'+i.get('href')  
# 2、获取超链接页面的详细信息
def get_html_link(link_list):
    for i in link_list:
        html_link=requests.get(i)
        html_link.encoding='utf-8'
        soup=BeautifulSoup(html_link.text,'lxml')
        title=soup.find('div',class_="article-intro").h1.string
        con=soup.find('div',class_="article-intro").find_all('p')
        i=1
        list1=[]
        while True:
            if re.match('程序源代码',con[i].text) or re.match(' Python 100例',con[i].text) or re.match('以上实例输出结果为',con[i].text):
                break
            else:
                list1.append(con[i].text)
                i+=1
        yield (title,list1)
# 3、保存数据
def save_data(content_list):
    with open('G:/3.txt','w+',encoding='utf+8') as f:
        for tile,content in content_list:
            f.write(tile+'\n')
            for i in range(len(content)):
                f.write(content[i]+'\n')    
            f.write('#'*80+'\n')    
# 4、函数回调
def fun_call(url):
    link_list=get_html(url)
    content_list=get_html_link(link_list)
    save_data(content_list)
# 5、主函数
def main():
    url='http://www.runoob.com/python/python-100-examples.html'
    fun_call(url)
if __name__=='__main__':
    main()