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python爬虫---网页爬虫,图片爬虫,文章爬虫,Python爬虫爬取新闻网站新闻

零基础入门Python,给自己找了一个任务,做网站文章的爬虫小项目,因为实战是学代码的最快方式。所以从今天起开始写Python实战入门系列教程,也建议大家学Python时一定要多写多练。

目标

  • 1,学习Python爬虫
  • 2,爬取新闻网站新闻列表
  • 3,爬取图片
  • 4,把爬取到的数据存在本地文件夹或者数据库
  • 5,学会用pycharm的pip安装Python需要用到的扩展包

一,首先看看Python是如何简单的爬取网页的

1,准备工作

项目用的BeautifulSoup4和chardet模块属于三方扩展包,如果没有请自行pip安装,我是用pycharm来做的安装,下面简单讲下用pycharm安装chardet和BeautifulSoup4

  • 在pycharm的设置里按照下图的步骤操作

    ![Uploading 2_085587.png . . .]

  • 如下图搜索你要的扩展类库,如我们这里需要安装chardet直接搜索就行,然后点击install package, BeautifulSoup4做一样的操作就行

2.png

  • 安装成功后就会出现在在安装列表中,到此就说明我们安装网络爬虫扩展库成功

3.png

二,由浅入深,我们先抓取网页

我们这里以抓取简书首页为例:www.jianshu.com/

# 简单的网络爬虫
from urllib import request
import chardet

response = request.urlopen("http://www.jianshu.com/")
html = response.read()
charset = chardet.detect(html)# {'language': '', 'encoding': 'utf-8', 'confidence': 0.99}
html = html.decode(str(charset["encoding"]))  # 解码
print(html)

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由于抓取的html文档比较长,这里简单贴出来一部分给大家看下

<!DOCTYPE html>
<!--[if IE 6]><html class="ie lt-ie8"><![endif]-->
<!--[if IE 7]><html class="ie lt-ie8"><![endif]-->
<!--[if IE 8]><html class="ie ie8"><![endif]-->
<!--[if IE 9]><html class="ie ie9"><![endif]-->
<!--[if !IE]><!--> <html> <!--<![endif]-->

<head>
  <meta charset="utf-8">
  <meta http-equiv="X-UA-Compatible" content="IE=Edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0,user-scalable=no">

  <!-- Start of Baidu Transcode -->
  <meta http-equiv="Cache-Control" content="no-siteapp" />
  <meta http-equiv="Cache-Control" content="no-transform" />
  <meta name="applicable-device" content="pc,mobile">
  <meta name="MobileOptimized" content="width"/>
  <meta name="HandheldFriendly" content="true"/>
  <meta name="mobile-agent" content="format=html5;url=http://localhost/">
  <!-- End of Baidu Transcode -->

    <meta name="description"  content="简书是一个优质的创作社区,在这里,你可以任性地创作,一篇短文、一张照片、一首诗、一幅画……我们相信,每个人都是生活中的艺术家,有着无穷的创造力。">
    <meta name="keywords"  content="简书,简书官网,图文编辑软件,简书下载,图文创作,创作软件,原创社区,小说,散文,写作,阅读">
..........后面省略一大堆
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这就是Python3的爬虫简单入门,是不是很简单,建议大家多敲几遍

三,Python3爬取网页里的图片并把图片保存到本地文件夹

目标

  • 爬取百度贴吧里的图片
  • 把图片保存到本地,都是妹子图片奥 不多说,直接上代码,代码里的注释很详细。大家仔细阅读注释就可以理解了
import re
import urllib.request

#爬取网页html
def getHtml(url):
    page = urllib.request.urlopen(url)
    html = page.read()
    return html


html = getHtml("http://tieba.baidu.com/p/3205263090")
html = html.decode('UTF-8')

#获取图片链接的方法
def getImg(html):
    # 利用正则表达式匹配网页里的图片地址
    reg = r'src="([.*\S]*\.jpg)" pic_ext="jpeg"'
    imgre=re.compile(reg)
    imglist=re.findall(imgre,html)
    return imglist

imgList=getImg(html)
imgCount=0
#for把获取到的图片都下载到本地pic文件夹里,保存之前先在本地建一个pic文件夹
for imgPath in imgList:
    f=open("../pic/"+str(imgCount)+".jpg",'wb')
    f.write((urllib.request.urlopen(imgPath)).read())
    f.close()
    imgCount+=1
print("全部抓取完成")

复制代码

迫不及待的看下都爬取到了些什么美图

4.png

就这么轻易的爬取到了24个妹子的图片。是不是很简单。

四,Python3爬取新闻网站新闻列表

  • 这里我们只爬取新闻标题,新闻url,新闻图片链接。
  • 爬取到的数据目前只做展示,等我学完Python操作数据库以后会把爬取到的数据保存到数据库。

到这里稍微复杂点,就分布给大家讲解

  • 1 这里我们需要先爬取到html网页上面第一步有讲怎么抓取网页
  • 2分析我们要抓取的html标签

5.png
分析上图我们要抓取的信息再div中的a标签和img标签里,所以我们要想的就是怎么获取到这些信息

这里就要用到我们导入的BeautifulSoup4库了,这里的关键代码

# 使用剖析器为html.parser
soup = BeautifulSoup(html, 'html.parser')
# 获取到每一个class=hot-article-img的a节点
allList = soup.select('.hot-article-img')
复制代码

上面代码获取到的allList就是我们要获取的新闻列表,抓取到的如下

[<div class="hot-article-img">
<a href="/article/211390.html" target="_blank">
![](https://img.huxiucdn.com/article/cover/201708/22/173535862821.jpg?imageView2/1/w/280/h/210/|imageMogr2/strip/interlace/1/quality/85/format/jpg)
</a>
</div>, <div class="hot-article-img">
<a href="/article/214982.html" target="_blank" title="TFBOYS成员各自飞,商业价值天花板已现?">
<!--视频和图片保留一个-->
![](https://img.huxiucdn.com/article/cover/201709/17/094856378420.jpg?imageView2/1/w/280/h/210/|imageMogr2/strip/interlace/1/quality/85/format/jpg)
</a>
</div>, <div class="hot-article-img">
<a href="/article/213703.html" target="_blank" title="买手店江湖">
<!--视频和图片保留一个-->
![](https://img.huxiucdn.com/article/cover/201709/17/122655034450.jpg?imageView2/1/w/280/h/210/|imageMogr2/strip/interlace/1/quality/85/format/jpg)
</a>
</div>, <div class="hot-article-img">
<a href="/article/214679.html" target="_blank" title="iPhone X正式告诉我们,手机和相机开始分道扬镳">
<!--视频和图片保留一个-->
![](https://img.huxiucdn.com/article/cover/201709/14/182151300292.jpg?imageView2/1/w/280/h/210/|imageMogr2/strip/interlace/1/quality/85/format/jpg)
</a>
</div>, <div class="hot-article-img">
<a href="/article/214962.html" target="_blank" title="信用已被透支殆尽,乐视汽车或成贾跃亭弃子">
<!--视频和图片保留一个-->
![](https://img.huxiucdn.com/article/cover/201709/16/210518696352.jpg?imageView2/1/w/280/h/210/|imageMogr2/strip/interlace/1/quality/85/format/jpg)
</a>
</div>, <div class="hot-article-img">
<a href="/article/214867.html" target="_blank" title="别小看“搞笑诺贝尔奖”,要向好奇心致敬">
<!--视频和图片保留一个-->
![](https://img.huxiucdn.com/article/cover/201709/15/180620783020.jpg?imageView2/1/w/280/h/210/|imageMogr2/strip/interlace/1/quality/85/format/jpg)
</a>
</div>, <div class="hot-article-img">
<a href="/article/214954.html" target="_blank" title="10 年前改变世界的,可不止有 iPhone | 发车">
<!--视频和图片保留一个-->
![](https://img.huxiucdn.com/article/cover/201709/16/162049096015.jpg?imageView2/1/w/280/h/210/|imageMogr2/strip/interlace/1/quality/85/format/jpg)
</a>
</div>, <div class="hot-article-img">
<a href="/article/214908.html" target="_blank" title="感谢微博替我做主">
<!--视频和图片保留一个-->
![](https://img.huxiucdn.com/article/cover/201709/16/010410913192.jpg?imageView2/1/w/280/h/210/|imageMogr2/strip/interlace/1/quality/85/format/jpg)
</a>
</div>, <div class="hot-article-img">
<a href="/article/215001.html" target="_blank" title="苹果确认取消打赏抽成,但还有多少内容让你觉得值得掏腰包?">
<!--视频和图片保留一个-->
![](https://img.huxiucdn.com/article/cover/201709/17/154147105217.jpg?imageView2/1/w/280/h/210/|imageMogr2/strip/interlace/1/quality/85/format/jpg)
</a>
</div>, <div class="hot-article-img">
<a href="/article/214969.html" target="_blank" title="中国音乐的“全面付费”时代即将到来?">
<!--视频和图片保留一个-->
![](https://img.huxiucdn.com/article/cover/201709/17/101218317953.jpg?imageView2/1/w/280/h/210/|imageMogr2/strip/interlace/1/quality/85/format/jpg)
</a>
</div>, <div class="hot-article-img">
<a href="/article/214964.html" target="_blank" title="百丽退市启示录:“一代鞋王”如何与新生代消费者渐行渐远">
<!--视频和图片保留一个-->
![](https://img.huxiucdn.com/article/cover/201709/16/213400162818.jpg?imageView2/1/w/280/h/210/|imageMogr2/strip/interlace/1/quality/85/format/jpg)
</a>
</div>]
复制代码

这里数据是抓取到了,但是太乱了,并且还有很多不是我们想要的,下面就通过遍历来提炼出我们的有效信息

  • 3 提取有效信息
#遍历列表,获取有效信息
for news in allList:
    aaa = news.select('a')
    # 只选择长度大于0的结果
    if len(aaa) > 0:
        # 文章链接
        try:#如果抛出异常就代表为空
            href = url + aaa[0]['href']
        except Exception:
            href=''
        # 文章图片url
        try:
            imgUrl = aaa[0].select('img')[0]['src']
        except Exception:
            imgUrl=""
        # 新闻标题
        try:
            title = aaa[0]['title']
        except Exception:
            title = "标题为空"
        print("标题",title,"\nurl:",href,"\n图片地址:",imgUrl)
        print("==============================================================================================")
复制代码

这里添加异常处理,主要是有的新闻可能没有标题,没有url或者图片,如果不做异常处理,可能导致我们爬取的中断。

过滤后的有效信息

标题 标题为空 
url: https://www.huxiu.com/article/211390.html 
图片地址: https://img.huxiucdn.com/article/cover/201708/22/173535862821.jpg?imageView2/1/w/280/h/210/|imageMogr2/strip/interlace/1/quality/85/format/jpg
==============================================================================================
标题 TFBOYS成员各自飞,商业价值天花板已现? 
url: https://www.huxiu.com/article/214982.html 
图片地址: https://img.huxiucdn.com/article/cover/201709/17/094856378420.jpg?imageView2/1/w/280/h/210/|imageMogr2/strip/interlace/1/quality/85/format/jpg
==============================================================================================
标题 买手店江湖 
url: https://www.huxiu.com/article/213703.html 
图片地址: https://img.huxiucdn.com/article/cover/201709/17/122655034450.jpg?imageView2/1/w/280/h/210/|imageMogr2/strip/interlace/1/quality/85/format/jpg
==============================================================================================
标题 iPhone X正式告诉我们,手机和相机开始分道扬镳 
url: https://www.huxiu.com/article/214679.html 
图片地址: https://img.huxiucdn.com/article/cover/201709/14/182151300292.jpg?imageView2/1/w/280/h/210/|imageMogr2/strip/interlace/1/quality/85/format/jpg
==============================================================================================
标题 信用已被透支殆尽,乐视汽车或成贾跃亭弃子 
url: https://www.huxiu.com/article/214962.html 
图片地址: https://img.huxiucdn.com/article/cover/201709/16/210518696352.jpg?imageView2/1/w/280/h/210/|imageMogr2/strip/interlace/1/quality/85/format/jpg
==============================================================================================
标题 别小看“搞笑诺贝尔奖”,要向好奇心致敬 
url: https://www.huxiu.com/article/214867.html 
图片地址: https://img.huxiucdn.com/article/cover/201709/15/180620783020.jpg?imageView2/1/w/280/h/210/|imageMogr2/strip/interlace/1/quality/85/format/jpg
==============================================================================================
标题 10 年前改变世界的,可不止有 iPhone | 发车 
url: https://www.huxiu.com/article/214954.html 
图片地址: https://img.huxiucdn.com/article/cover/201709/16/162049096015.jpg?imageView2/1/w/280/h/210/|imageMogr2/strip/interlace/1/quality/85/format/jpg
==============================================================================================
标题 感谢微博替我做主 
url: https://www.huxiu.com/article/214908.html 
图片地址: https://img.huxiucdn.com/article/cover/201709/16/010410913192.jpg?imageView2/1/w/280/h/210/|imageMogr2/strip/interlace/1/quality/85/format/jpg
==============================================================================================
标题 苹果确认取消打赏抽成,但还有多少内容让你觉得值得掏腰包? 
url: https://www.huxiu.com/article/215001.html 
图片地址: https://img.huxiucdn.com/article/cover/201709/17/154147105217.jpg?imageView2/1/w/280/h/210/|imageMogr2/strip/interlace/1/quality/85/format/jpg
==============================================================================================
标题 中国音乐的“全面付费”时代即将到来? 
url: https://www.huxiu.com/article/214969.html 
图片地址: https://img.huxiucdn.com/article/cover/201709/17/101218317953.jpg?imageView2/1/w/280/h/210/|imageMogr2/strip/interlace/1/quality/85/format/jpg
==============================================================================================
标题 百丽退市启示录:“一代鞋王”如何与新生代消费者渐行渐远 
url: https://www.huxiu.com/article/214964.html 
图片地址: https://img.huxiucdn.com/article/cover/201709/16/213400162818.jpg?imageView2/1/w/280/h/210/|imageMogr2/strip/interlace/1/quality/85/format/jpg
==============================================================================================
复制代码

到这里我们抓取新闻网站新闻信息就大功告成了,下面贴出来完整代码

from bs4 import BeautifulSoup
from urllib import request
import chardet

url = "https://www.huxiu.com"
response = request.urlopen(url)
html = response.read()
charset = chardet.detect(html)
html = html.decode(str(charset["encoding"]))  # 设置抓取到的html的编码方式

# 使用剖析器为html.parser
soup = BeautifulSoup(html, 'html.parser')
# 获取到每一个class=hot-article-img的a节点
allList = soup.select('.hot-article-img')
#遍历列表,获取有效信息
for news in allList:
    aaa = news.select('a')
    # 只选择长度大于0的结果
    if len(aaa) > 0:
        # 文章链接
        try:#如果抛出异常就代表为空
            href = url + aaa[0]['href']
        except Exception:
            href=''
        # 文章图片url
        try:
            imgUrl = aaa[0].select('img')[0]['src']
        except Exception:
            imgUrl=""
        # 新闻标题
        try:
            title = aaa[0]['title']
        except Exception:
            title = "标题为空"
        print("标题",title,"\nurl:",href,"\n图片地址:",imgUrl)
        print("==============================================================================================")
复制代码

数据获取到了我们还要把数据存到数据库,只要存到我们的数据库里,数据库里有数据了,就可以做后面的数据分析处理,也可以用这些爬取来的文章,给app提供新闻api接口,当然这都是后话了,等我自学到Python数据库操作以后,会写一篇文章 《Python3实战入门数据库篇---把爬取到的数据存到数据库》

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