Catch same exception multiple times

Question

Is any way to continue executing try block if an exception is raised? I think that the aswer is no, but I think that the following code is ugly.

def preprocess(self, text):
    try:
        text = self.parser(text)
    except AttributeError:
        pass
    try:
        terms = [term for term in text if term not in self.stopwords]
        text = list_to_string(terms)
    except AttributeError:
        pass
    try:
        terms = [self.stemmer.stem(term) for term in text]
        text = list_to_string(terms)
    except AttributeError:
        pass
    return text

There is another way to do this in a pythonic form?

You can use the finally keyword [errors in python](https://docs.python.org/2/tutorial/errors.html) — omri_saadon, Feb 21 '17 at 20:07
@omri_saadon: yeah but the problem with that is that you do not know where the `try` has stopped and thus where to continue. The only solution would be to surround every statement with a `try`... — Willem Van Onsem, Feb 21 '17 at 20:08
@Arman: well afaik the question is how to continue processing after an exception has been raised. — Willem Van Onsem, Feb 21 '17 at 20:09
@WillemVanOnsem, If the exceptions were in a different kind, it could help.. just saying :) — omri_saadon, Feb 21 '17 at 20:10
@Arman I was thinking the same, considering in each `except`, there is just a `pass`? Maybe the pass is just being used for the example. I'm not really sure. — DrZoo, Feb 21 '17 at 20:12
Why does `AttributeError` occur? You can check for `parser`, `stemmer` etc attributes — alexey, Feb 21 '17 at 20:12
There are the same kind of execptions. If `parser`, `stopwords` or `stemmer` doesn't exist in the object, the call is `None.parser` for example — Marco Canora, Feb 21 '17 at 20:12
maybe with contextlib: `from contextlib import suppress with suppress(AttributeError):` — Jean-François Fabre, Feb 21 '17 at 20:14
@alexey "It is easier to ask for forgiveness than to ask permission" — Marco Canora, Feb 21 '17 at 20:15
@Jean-FrançoisFabre Thanks, that's the aswer that I want :) — Marco Canora, Feb 21 '17 at 20:20
I like easy rep, but that answer is already in the link provided when I closed the question as duplicate. Sounded perfect for your need indeed :) enjoy. — Jean-François Fabre, Feb 21 '17 at 20:23

score 2 · Answer 1 · answered Feb 21 '17 at 20:15

I would rewrite it in this way:

def preprocess(self, text):
    if hasattr(self, 'parser'): 
        text = self.parser(text)

    if hasattr(self, 'stopwords'): 
        terms = [term for term in text if term not in self.stopwords]
        text = list_to_string(terms)

    if hasattr(self, 'stemmer'):        
        terms = [self.stemmer.stem(term) for term in text]
        text = list_to_string(terms)

    return text

I think it's much easier to understand and would not catch AttributeError inside parser and stem calls

yes, it's better to avoid exceptions if possible. +1 for thinking outside the box of this duplicate question. — Jean-François Fabre, Feb 21 '17 at 20:24

Catch same exception multiple times

1 Answers1