re,xpath,BeautifulSoup三种方法爬取古诗词网上诗歌

re，xpath ，bs4对同一个页面的解析速度
发现re比xpath快接近10倍，xpath比bs4快接近10倍
可见要想追求极致速度，使用正则表达式解析有多重要

1、re解析的代码

# 使用正则表达式解析网页元素
# 关键点:直接找每个个体里面相同位置的元素，用findall一次提取出来到列表中
import requests
import re
DATA = []
def getHTMLtext(url,headers,timeout=10):
    try :
        resp = requests.get(url,headers=headers,timeout=timeout)
        resp.raise_for_status
        resp.encoding = 'utf-8'
        return resp.text
    except:
        return ''
def reParser(text):
    name_list = re.findall(r'<div class="yizhu".*?<b>(.*?)</b>',text,re.S)  #re.DOTALL
     
    dynasty_list = re.findall(r'<p class="source">.*?target="_blank">(.*?)</a>',text,re.S)
     
    author_list = re.findall(r'<p class="source">.*?target="_blank">.*?</a>.*?target="_blank">(.*?)</a>',text,re.S)
     
    row_content_list = re.findall(r'<div class="contson".*?>(.*?)</div>',text,re.S)
    content_list = []
    for content in row_content_list:
        temp = re.sub(r'<.*?>','',content)  #这里一定要记得不要写成了贪婪匹配哦
        content_list.append(temp.strip()) #去除空格
     
    likes_list = re.findall(r'<span> (\d*?)</span>',text,re.S)
     
    for value in zip(name_list,dynasty_list,author_list,content_list,likes_list):
        name,dynasty,author,content,likes = value
        poetry_dict = {
            '诗词名':name,
            '朝代':dynasty,
            '作者':author,
            '内容':content,
            '点赞数':likes
        }
        DATA.append(poetry_dict)
         
def print_poetry(data):
    for every_poetry in data:
            print(every_poetry['诗词名'])
            print(every_poetry['朝代'] + ':' + every_poetry['作者'] )
            print(every_poetry['内容'])
            print('有{}人喜欢这首诗(词)哦'.format(every_poetry["点赞数"]))
            print("\n"+'*'*50+"\n")
         
if __name__ == '__main__':
    row_url = 'https://www.gushiwen.org/default_{}.aspx'
    headers = {'User-Agent':'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/72.0.3626.109 Safari/537.36'}
    num = input('请输入要爬取的页数（1-100）:')
    for i in range(eval(num)):
        url = row_url.format(i+1)
        text = getHTMLtext(url,headers)
        if text == '':
            print('url: {} 访问失败'.format(url))
        else:
            reParser(text)
    DATA.sort(key=lambda x: int(x['点赞数']),reverse = True)
    TOP10 = DATA[:10]
    print_poetry(TOP10)

2、Xpath版本

from lxml import etree
DATA = []
def getHTMLtext(url,headers,timeout=10):
    try :
        resp = requests.get(url,headers=headers,timeout=timeout)
        resp.raise_for_status
        resp.encoding = 'utf-8'
        return resp.text
    except:
        return ''
def xpathParser(text):
    htmlElement = etree.HTML(text)  # <class 'lxml.etree._Element'>
    name_list = htmlElement.xpath('/html/body/div[2]/div[1]/div/div[1]/p[1]/a/b/text()')
    dynasty_list = htmlElement.xpath('/html/body/div[2]/div[1]/div/div[1]/p[2]/a[1]/text()')
    author_list = htmlElement.xpath('/html/body/div[2]/div[1]/div/div[1]/p[2]/a[2]/text()')
    content_list = []
    poetries = htmlElement.xpath('//div[@class="contson" and contains(@id,"contson")]') #返回一个列表，里面每一个都是'lxml.etree._Element'
   # print(etree.tostring(poetries[0],encoding = 'utf-8').decode('utf-8'))
    for poetry in poetries:
        row_content = ''.join(poetry.xpath('.//text()'))#这里的.可千万不能掉，否则会忽略掉poetry哦
        content_list.append(row_content.replace('\n',''))
    row_likes_list = htmlElement.xpath('//a[contains(@id,"agood")]/span/text()') 
    likes_list = [int(like.strip()) for like in row_likes_list]
    for value in zip(name_list,dynasty_list,author_list,content_list,likes_list):
        name,dynasty,author,content,likes = value
        poetry_dict = {
            '诗词名':name,
            '朝代':dynasty,
            '作者':author,
            '内容':content,
            '点赞数':likes
        }
        DATA.append(poetry_dict) 
 
def print_poetry(data):
    for every_poetry in data:
            print(every_poetry['诗词名'])
            print(every_poetry['朝代'] + ':' + every_poetry['作者'] )
            print(every_poetry['内容'])
            print('有{}人喜欢这首诗(词)哦'.format(every_poetry["点赞数"]))
            print("\n"+'*'*50+"\n")
         
if __name__ == '__main__':
    row_url = 'https://www.gushiwen.org/default_{}.aspx'
    headers = {'User-Agent':'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/72.0.3626.109 Safari/537.36'}
    num = input('请输入要爬取的页数（1-100）:')
    for i in range(eval(num)):
        url = row_url.format(i+1)
        text = getHTMLtext(url,headers)
        if text == '':
            print('url: {} 访问失败'.format(url))
        else:
            xpathParser(text)
    DATA.sort(key=lambda x: int(x['点赞数']),reverse = True)
    TOP10 = DATA[:10]
    print_poetry(TOP10)
3、bs4版本

# 使用bs4提取网页，先利用find_all解析
import requests
from bs4 import BeautifulSoup
DATA = []
def getHTMLtext(url,headers,timeout=10):
    try :
        resp = requests.get(url,headers=headers,timeout=timeout)
        resp.raise_for_status
        resp.encoding = 'utf-8'
        return resp.text
    except:
        return ''
def bs4_find_all_Parser(text):
    soup = BeautifulSoup(text,'lxml')
    sons = soup.find_all('div',class_ = "sons")[:10] #返回一个<class 'bs4.element.ResultSet'>，每一个元素都是Tag类型
    # 注意：上一步里面返回了一些其他的元素，我们可以提取出前面的10项，那是我们需要用到的
    for son in sons:
        name = son.find('b').string
        print(name)
        dynasty_author = son.find('p',class_="source").get_text()
        print(dynasty_author)
        content = son.find('div',class_="contson").get_text().strip()
        print(content)
        like = son.find_all('span')[1].string.strip()
        print('点赞数:'+like)
        print('\n'+'*'*30+'\n')
         
  
if __name__ == '__main__':
        url = 'https://www.gushiwen.org/default_1.aspx'
        headers = {'User-Agent':'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/72.0.3626.109 Safari/537.36'}
        text = getHTMLtext(url,headers)
        if text == '':
            print('url: {} 访问失败'.format(url))
        else:
            bs4_find_all_Parser(text)