пытаясь отладить этот пример онлайн лекции с помощью urllib2 - PullRequest
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пытаясь отладить этот пример онлайн лекции с помощью urllib2

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/ 16 апреля 2020

Привет, я новичок в python и купил онлайн-курс, и в нем показано, как создать программу, которая просит пользователя ввести URL-адрес, затем проверяет его действительность, а затем импортирует его в текстовый файл. это работает для инструктора, используя python 2.7, я использую то же самое, но не буду работать для меня, и теперь я не могу с этим справиться, пожалуйста, помогите. 

import urllib2
import sys
urlToRead = 'http://www.google.com'
# this value wont actually get used, because of the way the while loop below is setup.
# but while loops often need a dummy value like this to work right the first time.

while urlToRead != " ":
    try:
        urlToRead = input("Please enter the Next URL to crawl ")
        if urlToRead == "":
            print ("OK, Exiting loop")
            break
        shortName = input("Please enter a short name for that URL " + urlToRead) 
        webFile = urllib2.urlopen(urlToRead).read()
        #This line above uses a readymade function in the urllib2 module to do something super - cool:
        #Ot takes a url, goes to the website for that url, downloads the contents(which are in HTML format)
        # and returns them to be stored in a string variable (here called webFile)
        crawledWebLinks[shortName] = webFile
        # this line above places a key value pair (shrtname, html for that url) in the dictionary
    except:
        # this bit of caode - the intended lines following 'except:' will be executed if the code
        # in the 'try' block (the intended lines following) the 'try:' above throw and error
        # this is an example of something know as exception-handling, on which we will talk later
        print ("*********************\nUnexpected Error***********") ,sys.exc_info()[0]
        # The snip 'sys.exc_info()[0]' returns information about the last error that occurred-
        # this code is made available through the sys library that we imported above. 
        # Quite Magical
        stopOrProceed = input("Hmm..stop or proceed? Enter 1 to stop, enter anything else to continue")
        if stopOrProceed ==1 :
            print ("Okey-Dokey...Stopping\n")
            break
            # this break will brake out of the nearest loop - in this case, the while loop
        else:
            print ("Cool! Lets continue\n") 
            continue
            # this continue will skip out of the current iteration of this loop and move to the
            # next i.e. the loop will reset to the start
    print ("Note this indentation - this line is inside the while loop, but it is outside the try/catch block") 
print ("Note this indentation - this line is entirely outside the loop ")  
print (crawledWebLinks.keys()) 

output

Please enter the Next URL to crawl "http://www.google.com"
Please enter a short name for that URL http://www.google.com "google"
*********************
Unexpected Error*********** <type 'exceptions.NameError'>
Hmm..stop or proceed? Enter 1 to stop, enter anything else to continue
...