Level 3:
http://www.pythonchallenge.com/pc/def/equality.html
根据hints，打开page source code，查找前后各仅有3个大写字母包围的小写字母。
#!/usr/bin/python
import urllib.request
import re
"""
Python Challenge, Level 3:
http://www.pythonchallenge.com/pc/def/equality.html
"""
def main():
url = 'http://www.pythonchallenge.com/pc/def/equality.html'
resp = urllib.request.urlopen(url).read().decode()
match = re.search(r'<!--(.*?)-->', resp, re.DOTALL)
result = ''.join(re.findall(r'[^A-Z][A-Z]{3}([a-z])[A-Z]{3}[^A-Z]', match.group(1)))
print(result)
if __name__ == '__main__':
main()
得到结果linkedlist，还是老办法，替换url，进入下一关。
Level 4:
http://www.pythonchallenge.com/pc/def/linkedlist.php
图没懂，其实就是个链接，具体打开page source code可以看到。链接为一个php的页面，带有参数nothing，访问可以得到信息“and the next nothing is 44827”，参数值迭代更新；编码追踪，直至找到第一个非此类信息。
#!/usr/bin/python
import urllib.request
import re
"""
Python Challenge, Level 4:
http://www.pythonchallenge.com/pc/def/linkedlist.php
"""
def pingurl(common_url, initial):
while(initial):
url = common_url + initial
resp = urllib.request.urlopen(url).read().decode()
match = re.search(r'and the next nothing is (\d+)', resp)
if match :
initial = match.group(1)
print(initial)
else :
return resp
def main():
url = 'http://www.pythonchallenge.com/pc/def/linkedlist.php?nothing='
initial = '12345'
print(pingurl(url, initial))
if __name__ == '__main__':
main()
初始值12345，若干次访问后得到信息“Yes. Divide by two and keep going.”；对最后一个值16044整除2，作为新的初始值继续，最终得到peak.html。替换url，进入下一关：）