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I found the following web scraping code in Web Scraping with Python by Ryan Mitchel:

from urllib.request import urlopen 
from bs4 import BeautifulSoup 
import re 
pages = set() 
def getLinks(pageUrl): 
    global pages 
    html = urlopen(";+pageUrl) 
    bsObj = BeautifulSoup(html) 
    for link in bsObj.findAll("a", href=repile("^(/wiki/)")): 
        if 'href' in link.attrs:
            if link.attrs['href'] not in pages: 
            #find new page
                newPage = link.attrs['href'] 
                print(newPage) 
                pages.add(newPage) 
                getLinks(newPage) 
getLinks("")

I believe that in the findAll() for loop, all tag objects with href attributes that meet the criteria have already been retrieved. Why do we still need to check if the object has the href attribute afterward?

In my opinion, I think that this line code should be deleted: if 'href' in link.attrs: Do I think correctly?

本文标签： pythonWhy validate the href attribute twiceStack Overflow

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