Python爬蟲入門級別的三個案例教程
阿新 • • 發佈:2018-11-08
貼吧爬取
寫程式碼前,構思需要的功能塊;寫程式碼時,把各個功能模組名提前寫好
初始化
初始化必要引數,完成基礎設定 爬取百度貼吧lol吧:爬取地址中的get引數須傳遞(可以指定不同主題的貼吧和頁碼)
- 主題名
- 初始網址
- 請求頭
生成網址
生成每一頁的路由地址
- 根據列表生成式生成多個頁面的地址
下載
get請求給每一頁的地址,爬取頁面
儲存
儲存爬取結果到檔案中,把每一頁爬取結果寫入到對應名字的檔案中
控制流程
將以上爬取操作封裝到run函式中,方便外部物件呼叫,以後會在此新增多執行緒
- 生成要爬取的每一頁的路由地址
- 通過for迴圈遍歷每一個路由地址
- 對每個路由地址進行爬取和獲取頁碼操作,並進行儲存
原始碼
1 import requests 2 3 class TiebaSpider: 4 def __init__(self, tieba_name_crawl): 5 """ 6 初始化必要引數,完成基礎設定 7 爬取百度貼吧lol吧:爬取地址中的get引數須傳遞(可以指定不同主題的貼吧和頁碼) 8 """ 9 self.tieba_name = tieba_name_crawl 10 self.url_base = 'https://tieba.baidu.com/f?kw=' + tieba_name_crawl + '&ie=utf-8&pn={}' 11 self.headers = {'User-Agent': 'Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:61.0) Gecko/20100101 Firefox/61.0'} 12 13 def make_url(self): 14 """ 15 生成每一頁的路由地址 16 :return:(列表生成式) 17 """ 18 return [self.url_base.format(i) for i in range(4)] 19 20 def download_url(self, url_str): 21 """ 22 get請求給每一頁的地址,爬取頁面 23 :param url_str: 每一頁的路由地址 24 :return: 爬取的結果 25 """ 26 result = requests.get(url_str, headers=self.headers) 27 return result.text 28 29 def save_result(self, result, page_num): 30 """ 31 儲存爬取結果到檔案中 32 :param result: 每一頁的爬取結果 33 :param page_num: 頁碼,方便分類儲存 34 :return: 把每一頁爬取結果寫入到對應名字的檔案中 35 """ 36 # with open('./download/lol' + str(page_num) + '.html', 'ab') as f: 37 # f.write(result.encode('utf-8')) 38 file_path = './download/{}~第{}頁.html'.format(self.tieba_name,page_num) 39 with open(file_path,'wb') as f: 40 f.write(result.encode('utf-8')) 41 42 def run(self): 43 """ 44 將以上爬取操作封裝到run函式中,方便外部物件呼叫,以後會在此新增多執行緒 45 · 生成要爬取的每一頁的路由地址 46 · 通過for迴圈遍歷每一個路由地址 47 · 對每個路由地址進行爬取和獲取頁碼操作,並進行儲存 48 :return: 49 """ 50 url_lists = self.make_url() 51 for url_str in url_lists: 52 result_str = self.download_url(url_str) 53 p_num = url_lists.index(url_str) + 1 54 self.save_result(result=result_str,page_num=p_num) 55 56 if __name__ == '__main__': 57 tieba_spider = TiebaSpider('lol') 58 tieba_spider.run()
爬取糗事百科
1 import requests 2 from bs4 import BeautifulSoup 3 import lxml.html 4 5 class QiushiSpider: 6 def __init__(self): 7 """ 8 初始化必要引數,完成基礎設定 9 """ 10 # self.tieba_name = qiushi_name_crawl 11 # https: // www.qiushibaike.com / 8 12 # hr / page / 2 / 13 self.url_base = 'https://www.qiushibaike.com/8hr/page/{}/' 14 # self.url_base = 'https://tieba.baidu.com/f?kw=' + qiushi_name_crawl + '&ie=utf-8&pn={}' 15 self.headers = {'User-Agent': 'Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:61.0) Gecko/20100101 Firefox/61.0'} 16 17 def make_url(self): 18 return [self.url_base.format(i) for i in range(4)] 19 20 def download_url(self, url_str): 21 result = requests.get(url_str, headers=self.headers) 22 #---------- 23 # html = lxml.html.fromstring(result.text) 24 # html_data = html.xpath('//div[@class="content"]/span[1]/text()') 25 # data_all = [] 26 # # for h in html_data: 27 # # data_all.append(h) 28 # return html_data 29 #----------- 30 return result.text 31 32 def save_result(self, result, page_num): 33 with open('./download/qiushi' + str(page_num) + '.html', 'ab') as f: 34 f.write(result.encode('utf-8')) 35 36 37 # qiushi = QiushiSpider() 38 # qiushi_url = qiushi.make_url() 39 # j = 1 40 # for i in qiushi_url: 41 # qiushi_text = qiushi.download_url(url_str=i) 42 # qiushi.save_result(result=qiushi_text, page_num=j) 43 # j += 1
爬取網站資訊
BeautifulSoup方式
1 import requests
2 from bs4 import BeautifulSoup
3 class CountrySoup:
4 def __init__(self,country_name):
5 self.country_name = country_name
6 self.url_base = 'http://example.webscraping.com/places/default/view/{}'.format(self.country_name)
7 self.headers = {'User-Agent': 'Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:61.0) Gecko/20100101 Firefox/61.0',}
8
9 def download_url(self):
10 result = requests.get(self.url_base,headers=self.headers)
11 soup = BeautifulSoup(result.text,'lxml')
12 tr = soup.find(attrs={'id':"places_country__row"})
13 print(tr,type(tr))
14 td = tr.find(attrs={'class':"w2p_fw"})
15 print(td,type(td))
16
17 print(td.text)
lxml方式
1 class CountrySpider:
2 def __init__(self,country_name):
3 self.country_name = country_name
4 self.url_base = 'http://example.webscraping.com/places/default/view/{}'.format(self.country_name)
5 self.headers = {'User-Agent': 'Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:61.0) Gecko/20100101 Firefox/61.0',}
6
7 def download_url(self,url_str):
8 result = requests.get(url_str,headers=self.headers)
9 html = lxml.html.fromstring(result.text)
10 data_country = html.xpath('//tr[@id="places_country__row"]/td[@class="w2p_fw"]/text()')
11 data_capital = html.xpath('//tr[@id="places_capital__row"]/td[@class="w2p_fw"]/text()')
12 data_area = html.xpath('//tr[@id="places_area__row"]/td[@class="w2p_fw"]/text()')
13 data_all = ['國家:'+data_country[0],'首都:'+data_capital[0],'國土面積:'+data_area[0]]
14 return data_all
15 # print(html_data)
16
17 def save_result(self,result):
18 print(type(result),result)
19 for r in result:
20 r = r + '\n'
21 with open('./country.txt','ab') as f:
22 f.write(r.encode('utf-8'))
23 # with open('./country.txt','ab') as f:
24 # f.writelines(result)
25 def run(self):
26 result = self.download_url(self.url_base)
27 self.save_result(result)
28
29
30 if __name__ == '__main__':
31 # c = CountrySpider('Bolivia-27')
32 # c.run()
33 s = CountrySoup('Bolivia-27')
34 s.download_url()