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今天下午在写python爬虫时发现了一个有意思的事
先放两段代码和输出 1.from bs4 import BeautifulSoupimport urllib2req = urllib2.urlopen("https://www.qidian.com/all?orderId=&style=1&pageSize=20&siteid=1&pubflag=0&hiddenField=0&page=1")html = req.read()soup = BeautifulSoup(html,'lxml')for div in soup.find_all('div',class_="book-img-box"): for a in div.find_all('a'): print 'https:',a['href']＃重点在这一句 输出：
https: //book.qidian.com/info/1004608738https: //book.qidian.com/info/1010468795https: //book.qidian.com/info/1009265821https: //book.qidian.com/info/1003694333https: //book.qidian.com/info/1005238666https: //book.qidian.com/info/1003723851https: //book.qidian.com/info/1009704712https: //book.qidian.com/info/1005986994https: //book.qidian.com/info/1004595892https: //book.qidian.com/info/1003354631https: //book.qidian.com/info/1003578885https: //book.qidian.com/info/1010136878https: //book.qidian.com/info/1010734492https: //book.qidian.com/info/1010734486https: //book.qidian.com/info/1003307568https: //book.qidian.com/info/1004142144https: //book.qidian.com/info/1010422436https: //book.qidian.com/info/1010298084https: //book.qidian.com/info/3638453https: //book.qidian.com/info/3676417
第二种输入
from bs4 import BeautifulSoupimport urllib2req = urllib2.urlopen("https://www.qidian.com/all?orderId=&style=1&pageSize=20&siteid=1&pubflag=0&hiddenField=0&page=1")html = req.read()soup = BeautifulSoup(html,'lxml')for div in soup.find_all('div',class_="book-img-box"): for a in div.find_all('a'): print 'https:'＋a['href']＃重点在这一句 输出：
https://book.qidian.com/info/1004608738https://book.qidian.com/info/1010468795https://book.qidian.com/info/1009265821https://book.qidian.com/info/1003694333https://book.qidian.com/info/1005238666https://book.qidian.com/info/1003723851https://book.qidian.com/info/1009704712https://book.qidian.com/info/1005986994https://book.qidian.com/info/1004595892https://book.qidian.com/info/1003354631https://book.qidian.com/info/1003578885https://book.qidian.com/info/1010136878https://book.qidian.com/info/1010734492https://book.qidian.com/info/1010734486https://book.qidian.com/info/1003307568https://book.qidian.com/info/1004142144https://book.qidian.com/info/1010422436https://book.qidian.com/info/1010298084https://book.qidian.com/info/3638453https://book.qidian.com/info/3676417
综合看两段输出，是不是发现第一次输出的https://和book…之间存在空格，而第二次输出没有呢？对的，在python2.7中用‘＋‘号连接会导致输出无空格间隙，用‘，‘连接会导致输出存在空格
编程体会，说的不好，若有错误请指出，谢谢
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