#coding=utf-8from bs4 import BeautifulSoupimport urllib.requestfor i in range(1,54):    url = "http://www.cnblogs.com/php-linux/?page="+str(i)    res = urllib.request.urlopen(url)    soup = BeautifulSoup(res,'lxml')    book_div = soup.find(attrs={'id':"mainContent"})    book_a = book_div.findAll(attrs={"class":'postTitle2'})    f = open('a.txt',"a",encoding='utf8')    for book in book_a :        f.write(book.string+str("链接:")+ str(book.get('href')) + "\n")    f.close()    print("保存成功"+ book.string+str("链接:")+ str(book.get('href')))