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Re: Python Style Question

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Date Wed, 29 Oct 2014 12:52:25 +0100
Subject Re: Python Style Question
From Rafael Romero Carmona <rafaelromcar@gmail.com>
Cc "python-list@python.org" <python-list@python.org>
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2014-10-29 12:25 GMT+01:00 Martin Kemp <martin.kemp@ingg.com>:
> -----BEGIN PGP SIGNED MESSAGE-----
> Hash: SHA1
>
> On 29/10/2014 10:45, Anton wrote:
>> Let's say I have an incoming list of values *l*. Every element of
>> *l* can be one of the following options: 1) an integer value 2) a
>> string in form of '<int_value>', e.g. '7' 3) a string with a json
>> serialization of an integer value, e.g. '"7"' 4) something else
>> that should be ignored
>>
>> I need to transform this list into another list with values from
>> options 1)-3) coerced to int. The code below should do this.
>>
>>
>> Variant 1 ===
>>
>> values = [] for c in l: # Case 1) or 2) try: c_int = int(c) except
>> ValueError: pass else: values.add(c_int) continue
>>
>> # Case 3) try: c_int = int(json.loads(c)) except ValueError: pass
>> else: values.add(c_int) continue
>>
>> ===
>>
>> Is this code ugly? Does it follow EAFP? Am I missing something in
>> language best practice?
>>
>> Or maybe below is more preferable way with a nested try...except
>> clause?
>>
>> Variant 2 === values = [] for c in l: # Case 1) or 2) try: c_int =
>> int(c) except ValueError:  # Case 3) try: c_int =
>> int(json.loads(c)) except ValueError: pass else: values.add(c_int)
>> continue  else: values.add(c_int) continue ===
>>
>> Thanks, Anton.
>>
>>
>
> Your first example is perfectly fine and is EAFP
>

Actually it doesn't work because there is no add function and it
doesn't catch the TypeError function to ignore other exceptions than
ValueError. Doesn't it? I tested in Python 2.7.6 and 3.4.

> Personally, I prefer to avoid nesting when it's not necessary.
>
> - --
> Martin Kemp (martin.kemp@ingg.com)
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> --
> https://mail.python.org/mailman/listinfo/python-list

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Thread

Python Style Question Anton <anton.schattenfeld@gmail.com> - 2014-10-29 03:42 -0700
  Re: Python Style Question Martin Kemp <martin.kemp@ingg.com> - 2014-10-29 11:25 +0000
  Re: Python Style Question Rafael Romero Carmona <rafaelromcar@gmail.com> - 2014-10-29 12:09 +0100
    Re: Python Style Question Anton <anton.schattenfeld@gmail.com> - 2014-10-29 12:09 -0700
  Re: Python Style Question Rafael Romero Carmona <rafaelromcar@gmail.com> - 2014-10-29 12:52 +0100
    Re: Python Style Question Anton <anton.schattenfeld@gmail.com> - 2014-10-29 12:23 -0700
  Re: Python Style Question Martin Kemp <martin.kemp@ingg.com> - 2014-10-29 12:42 +0000
  Re: Python Style Question Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2014-10-30 22:10 +1100
    Re: Python Style Question MRAB <python@mrabarnett.plus.com> - 2014-10-30 12:21 +0000
      Re: Python Style Question Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2014-10-31 09:48 +1100
        Re: Python Style Question Denis McMahon <denismfmcmahon@gmail.com> - 2014-10-31 04:55 +0000
    Re: Python Style Question Roy Smith <roy@panix.com> - 2014-10-30 20:34 -0400
      Re: Python Style Question Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2014-10-31 14:52 +1100
    Re: Python Style Question Anton <anton.schattenfeld@gmail.com> - 2014-11-12 12:31 -0800

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