urlopen（）上的python urllib2多个try语句

Question

So, simply I want to be able to run a for across a list of URLs, if one fails then I want to continue on to try the next.

I've tried using the following but sadly it throws and exception if the first URL doesn't work.

servers = ('http://www.google.com', 'http://www.stackoverflow.com')
for server in servers:
    try:
        u = urllib2.urlopen(server)
    except urllib2.URLError:
        continue
    else:
        break
else:
    raise

Any ideas?

Thanks in advance.

Answer 1

servers = ('http://www.google.com', 'http://www.stackoverflow.com')
for server in servers:
    try:
        u = urllib2.urlopen(server)
    except urllib2.URLError:
        continue
    else:
        break
else:
    raise

This code breaks out of the loop if the url connection doesn't raise an error ( else: break part).

Do you want the 2nd one used only if the first fails?

edit: I thought that the else: following the for loop should raise because of the break , but in my quick test that didn't work ... because my understanding of for/else was wrong

Answer 2

So the problem turned out to be user error. I was trying stupid domains like "wegwegwe.com" but I never actually had a usable domain in the list, so eventually it did just raise the exception.

User error.