NameError：名稱 '的htmlText' 沒有定義

Question

我得到一個錯誤，當我運行此腳本：

import urllib.request 
import urllib.parse 
from bs4 import BeautifulSoup 

url = "http://nytimes.com,http://nytimes.com" 

urls = [url] #stack of urls to scrape 
visited = [url] #historic record of urls 

while len(urls) >0: 
try: 
    htmltext = urllib.request.urlopen(urls[0]).read() 
except: 
    print(htmltext) 

原素文字：

import urllib.request 
import urllib.parse 
from bs4 import BeautifulSoup 

url = "http://nytimes.com,http://nytimes.com" 

urls = [url] #stack of urls to scrape 
visited = [url] #historic record of urls 

while len(urls) >0: 
try: 
    htmltext = urllib.request.urlopen(urls[0]).read() 
except: 
    print(urls[0]) 
soup = BeautifulSoup(htmltext) 

urls.pop(0) 

print (soup.findAll('a',href=True)) 

錯誤：

socket.gaierror: [Errno -2] Name or service not known

urllib.error.URLError: urlopen error [Errno -2] Name or service not known

Traceback (most recent call last):

NameError: name 'htmltext' is not defined

Answer 1

如果urllib.request.urlopen()引發一個例外，htmltext永遠不會被分配一個值（所以打印該值在except不會窩RK）。

至於爲什麼urlopen()無法正常工作，請確保您傳遞的是有效的網址。