Hi Zero,
I see! This is very helpful. Thank you.
- Yingjie
On Aug 19, 2011, at 3:30 PM, Zero Piraeus wrote:
> :
>
> On 19 August 2011 15:09, Yingjie Lin <yingjie....@mssm.edu> wrote:
>>
>> I have been using try...except statements in the situations where I can
>> expect a certain type of errors might occur.
>> But sometimes I don't exactly know the possible error types, or sometimes I
>> just can't "spell" the error types correctly.
>> For example,
>>
>> try:
>> response = urlopen(urljoin(uri1, uri2))
>> except urllib2.HTTPError:
>> print "URL does not exist!"
>>
>> Though "urllib2.HTTPError" is the error type reported by Python, Python
>> doesn't recognize it as an error type name.
>> I tried using "HTTPError" alone too, but that's not recognized either.
>>
>> Does anyone know what error type I should put after the except statement? or
>> even better: is there a way not to specify
>> the error types? Thank you.
>
> You should always specify the error type, so that your error-handling
> code won't attempt to handle an error it didn't anticipate and cause
> even more problems.
>
> In this case, I think it's just that you haven't imported HTTPError
> into your namespace - if you do, it works:
>
>>>> from urllib2 import urlopen, HTTPError
>>>> try:
> ... response = urlopen("http://google.com/invalid";)
> ... except HTTPError:
> ... print "URL does not exist!"
> ...
> URL does not exist!
>>>>
>
> Alternatively:
>
>>>> import urllib2
>>>> try:
> ... response = urllib2.urlopen("http://google.com/invalid";)
> ... except urllib2.HTTPError:
> ... print "URL does not exist!"
> ...
> URL does not exist!
>>>>
>
> A careful look at the difference between these two ought to make it
> clear what's going on.
>
> -[]z.
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