38

What does the line del taglist[:] do in the code below?

import urllib
from bs4 import BeautifulSoup
taglist=list()
url=raw_input("Enter URL: ")
count=int(raw_input("Enter count:"))
position=int(raw_input("Enter position:"))
for i in range(count):
    print "Retrieving:",url
    html=urllib.urlopen(url).read()
    soup=BeautifulSoup(html)
    tags=soup('a')
    for tag in tags:
        taglist.append(tag)
    url = taglist[position-1].get('href', None)
    del taglist[:]
print "Retrieving:",url

The question is "write a Python program that expands on http://www.pythonlearn.com/code/urllinks.py. The program will use urllib to read the HTML from the data files below, extract the href= vaues from the anchor tags, scan for a tag that is in a particular position relative to the first name in the list, follow that link and repeat the process a number of times and report the last name you find". Sample problem: Start at http://python-data.dr-chuck.net/known_by_Fikret.html Find the link at position 3 (the first name is 1). Follow that link. Repeat this process 4 times. The answer is the last name that you retrieve. Sequence of names: Fikret Montgomery Mhairade Butchi Anayah Last name in sequence: Anayah

Sourav
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1 Answers1

50

[:] is the array slice syntax for every element in the array.

This answer here goes more in depth of the general uses: How slicing in Python works

del arr # Deletes the array itself
del arr[:]  # Deletes all the elements in the array
del arr[2]  # Deletes the third element in the array
del arr[1:]  # etc..
William Francis Gomes
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khazhyk
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