Python 如何在beautifulsoup中生成url字符串

我看了一些教程，读了一本关于beautifulsoup的基础知识的书，写了这个刮板，但无法让它循环浏览URL a-z或浏览页面。对于这个项目，我刮一个网站，我希望能够有它刮a-Z，而不仅仅是一个页面的结果

下面的代码一直在工作，直到我试图让它生成最后一个字母字符串--

下面是我不工作的代码-我试图构建url字符串。理想情况下，我会喜欢从一个文件或预定义的列表以及婴儿步骤拉

我的错误如下 ---------------------

---

该特定站点没有“x”。因此，您将获得404。用try包装它，这样它将跳过404页，并且应该可以工作

playerdatasaved=""
for letter in ascii_lowercase:
    try:
        soup = make_soup("http://www.basketball-reference.com/players/" + letter +      "/")
        for record in soup.find_all("tr"):
        playerdata=""
        for data in record.findAll("td"):
            playerdata=playerdata+","+data.text
        if len(playerdata)!=0:
            playerdatasaved = playerdatasaved + "\n" + playerdata[1:]
    except:
        pass

---

错误表明找不到带有该url的响应，因此您正在生成一个在相应服务器中不可用的url。我也这么认为，但您能告诉我原因吗？任何带有a-z的url都应该是有效的-我的设置有什么问题？我发布了第一个版本，爬行一个url-需要多个。我不能告诉你为什么服务器决定按照程序员的预期方式工作。同样在你的例子中，根据你的回答，看起来“X”不可用（404）。我想你不明白我的目标。标题和我的问题是“如何在beautifulsoup中生成url字符串”。我有一个url的第一部分工作，还有我的尝试发布，似乎非常接近工作，但很明显，我如何生成url的最后一部分出了问题。

Traceback (most recent call last):
 File "C:/Python36/web_scraper_tutorial/multiple_url_2.py", line 15, in <module>
 soup = make_soup("http://www.basketball-reference.com/players/" + letter + "/")
 File "C:/Python36/web_scraper_tutorial/multiple_url_2.py", line 8, in    make_soup
   thepage = urllib.request.urlopen(url)
 File "C:\Python36\lib\urllib\request.py", line 223, in urlopen
  return opener.open(url, data, timeout)
  File "C:\Python36\lib\urllib\request.py", line 532, in open
  response = meth(req, response)
 File "C:\Python36\lib\urllib\request.py", line 642, in http_response
 'http', request, response, code, msg, hdrs)
 File "C:\Python36\lib\urllib\request.py", line 564, in error
   result = self._call_chain(*args)
 File "C:\Python36\lib\urllib\request.py", line 504, in _call_chain
 result = func(*args)
 File "C:\Python36\lib\urllib\request.py", line 756, in http_error_302
 return self.parent.open(new, timeout=req.timeout)
 File "C:\Python36\lib\urllib\request.py", line 532, in open
 response = meth(req, response)
 File "C:\Python36\lib\urllib\request.py", line 642, in http_response
'http', request, response, code, msg, hdrs)
 File "C:\Python36\lib\urllib\request.py", line 570, in error
 return self._call_chain(*args)
 File "C:\Python36\lib\urllib\request.py", line 504, in _call_chain
 result = func(*args)
 File "C:\Python36\lib\urllib\request.py", line 650, in http_error_default
 raise HTTPError(req.full_url, code, msg, hdrs, fp)
 urllib.error.HTTPError: HTTP Error 404: Not Found

import urllib
import urllib.request
from bs4 import BeautifulSoup
import os

def make_soup(url):
thepage = urllib.request.urlopen(url)
soupdata = BeautifulSoup(thepage, "html.parser")
return soupdata

playerdatasaved=""
soup = make_soup("http://www.basketball-reference.com/players/a/")
for record in soup.find_all("tr"):
playerdata = ""
for data in record.findAll("td"):
    playerdata=playerdata+","+data.text
playerdatasaved = playerdatasaved + "\n" + playerdata[1:]

header="Player,From,To,Pos,Ht,Wt,Birth Date,College"+"\n"
file = open(os.path.expanduser("Basketball.csv"),"wb")
file.write(bytes(header, encoding="ascii",errors="ignore"))
file.write(bytes(playerdatasaved, encoding="ascii",errors="ignore"))


print(playerdatasaved)

playerdatasaved=""
for letter in ascii_lowercase:
    try:
        soup = make_soup("http://www.basketball-reference.com/players/" + letter +      "/")
        for record in soup.find_all("tr"):
        playerdata=""
        for data in record.findAll("td"):
            playerdata=playerdata+","+data.text
        if len(playerdata)!=0:
            playerdatasaved = playerdatasaved + "\n" + playerdata[1:]
    except:
        pass