how can i ignore error in python properly?

Question

I'm trying to web scraping.

using BeautifulSoup, i'm parsing several objects and confronted with a problem.

The problem is, i can't predict where the error occur using "find" method.

it looks like

a = soup.find(something).find(something)
b = soup.find(something)
...
f = soup.find(something).find(something)

among a,b,c,d,e,f, error can happen anywhere and their code should not be revised.

the variable 'b' is not matter because it would be None, which is ok.

but variable 'a' or 'f' is problem, because it would end the script.

i know there is "try - exception" grammar but that's not what i want. of course it can be written like this:

try : 
 a = soup.find(something).find(something)
except Exception:
 a = None
...
try : 
 f = soup.find(something).find(something)
except Exception:
 f = None

looks ridiculous, doesnt it?

how can i handle it gracefully?

The problem is that you are chaining two function call that are not guaranteed to find whatever you need. What I would do is check if it's possible to combine the `soup.find(something).find(something)` into `soup.find(something)`. — Yacine Mahdid, May 30 '20 at 19:26
@YacineMahdid you're right. but the second 'find' method has no attribute to distinguished. maybe i need to make it into 2 steps. thank you anyway — cjlee, May 30 '20 at 20:16

score 0 · Answer 1 · answered May 30 '20 at 19:20

0

I hope this solves your issue here. Just add pass in except statement

except:
    pass

answered May 30 '20 at 19:20

thealpha93

780
4
15

FYI--`except: pass` is [considered an anti-pattern](https://realpython.com/the-most-diabolical-python-antipattern/) – DarrylG May 30 '20 at 19:46
Sorry but that way is not what i want. if error occur while assigning a, then rest variables(b,c,d,e,f) would not be defined, right? – cjlee May 30 '20 at 20:13

score 0 · Answer 2 · answered May 30 '20 at 19:27

0

in your case you should use:

try:
    f = soup.find(something).find(something)
except AttributeError:
    f = None

answered May 30 '20 at 19:27

Олег Гребчук

539
3
11

but there are several variables should be assigned. sorry but this is not what i want. thanks anyway. – cjlee May 30 '20 at 20:17
each exception depend on situation – Олег Гребчук May 30 '20 at 20:36

maryanne · Accepted Answer · 2020-05-30T19:37:44.877

0

Would breaking this up into two steps solve the problem?

Something like:

a = soup.find(something)
if a is not None:
    a = a.find(something)

If not, I agree with the AttributeError suggestion.

You may find this question about exception handling interesting/helpful.

edited May 30 '20 at 19:37

answered May 30 '20 at 19:29

maryanne

109
4

how can i ignore error in python properly?

3 Answers3