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Re: A small question about PEP 8

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  Re: A small question about PEP 8 Joshua Landau <joshua.landau.ws@gmail.com> - 2013-07-08 11:39 +0100
    Re: A small question about PEP 8 Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-07-08 12:02 +0000
      Re: A small question about PEP 8 Dave Angel <davea@davea.name> - 2013-07-08 08:33 -0400
      Re: A small question about PEP 8 Joshua Landau <joshua.landau.ws@gmail.com> - 2013-07-08 14:07 +0100

#50142 — Re: A small question about PEP 8

On 8 July 2013 00:32, Xue Fuqiao <xfq.free@gmail.com> wrote:
> Hi all,
>
> (English is not my native language; please excuse typing errors.)
>
> I'm a Python newbie and just started reading PEP 8.  PEP says:
>
> -----------------------------------------------------------------------
> |The closing brace/bracket/parenthesis on multi-line constructs may
> |either line up under the last item of the list, as in:
> |
> |my_list = [
> |    1, 2, 3,
> |    4, 5, 6,
> |    ]
> |result = some_function_that_takes_arguments(
> |    'a', 'b', 'c',
> |    'd', 'e', 'f',
> |    )
> -----------------------------------------------------------------------
>
> I think the last item in my_list/result is 6/'f', respectively.  So why
> doesn't the bracket/paren line up _under_ the last item?  ISTM the code
> isn't consistent with the description.
>
> I have searched the archive of c.l.p and the web, but nothing helped.
> Can anyone point me in the right direction?

You will grow to be a wonderful pedant. What it means is that the
indentation will match the last one. Imagine:

"""
a_wonderful_set_of_things = {
    bannanas_made_of_apples,
    chocolate_covered_horns,
    doors_that_slide,
    china_but_on_the_moon,
    buffalo_with_windy_hair,
    not_missing_an_end_brace
"""¹

Now, there are several places you can put the end brace. You can (be a
massive fool and) put it after the last item:

"""
a_wonderful_set_of_things = {
    ...,
    not_missing_an_end_brace}
"""

You can also (be a fool and) put it at the same *indentation*:

"""
a_wonderful_set_of_things = {
    ...,
    not_missing_an_end_brace
    }
"""

Or you can (be sane) and put it at no indentation:

"""
a_wonderful_set_of_things = {
    ...,
    not_missing_an_end_brace
}
"""

Theoretically, there are more places you could put it (but we won't go
there... *shudder*).

The second of these is the one that PEP 8 was trying to explain. I
agree wording could be improved, but hey. You can file a bug report at
bugs.python.org if you care enough.

¹}

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#50148

On Mon, 08 Jul 2013 11:39:21 +0100, Joshua Landau wrote:

> On 8 July 2013 00:32, Xue Fuqiao <xfq.free@gmail.com> wrote:
>> Hi all,
>>
>> (English is not my native language; please excuse typing errors.)
>>
>> I'm a Python newbie and just started reading PEP 8.  PEP says:
>>
>> -----------------------------------------------------------------------
>> |The closing brace/bracket/parenthesis on multi-line constructs may
>> |either line up under the last item of the list, as in: |
>> |my_list = [
>> |    1, 2, 3,
>> |    4, 5, 6,
>> |    ]
>> |result = some_function_that_takes_arguments(
>> |    'a', 'b', 'c',
>> |    'd', 'e', 'f',
>> |    )
>> -----------------------------------------------------------------------
>>
>> I think the last item in my_list/result is 6/'f', respectively.  So why
>> doesn't the bracket/paren line up _under_ the last item?  ISTM the code
>> isn't consistent with the description.
>>
>> I have searched the archive of c.l.p and the web, but nothing helped.
>> Can anyone point me in the right direction?
> 
> You will grow to be a wonderful pedant. What it means is that the
> indentation will match the last one.

That's obvious from the example given, but that's nothing like the 
description given.




 Imagine:
> 
> """
> a_wonderful_set_of_things = {
>     bannanas_made_of_apples,
>     chocolate_covered_horns,
>     doors_that_slide,
>     china_but_on_the_moon,
>     buffalo_with_windy_hair,
>     not_missing_an_end_brace
> """¹
> 
> Now, there are several places you can put the end brace. You can (be a
> massive fool and) put it after the last item:
> 
> """
> a_wonderful_set_of_things = {
>     ...,
>     not_missing_an_end_brace}
> """

Well, call me a fool then, because when I have code that extends over 
*one* additional line, I prefer that:

    raise ValueError(
            "Some error message too long to fit on the above line")

rather than:

    raise ValueError(
            "Some error message too long to fit on the above line"
            )


> You can also (be a fool and) put it at the same *indentation*:
> 
> """
> a_wonderful_set_of_things = {
>     ...,
>     not_missing_an_end_brace
>     }
> """

Call me a fool again, since I prefer this when there are more than one 
additional line. At least this time I'm in good company, since that's 
recommended by PEP 8.


> Or you can (be sane) and put it at no indentation:
> 
> """
> a_wonderful_set_of_things = {
>     ...,
>     not_missing_an_end_brace
> }
> """

I consider that the least aesthetically pleasing, and also rather awkward:


some_result = some_function(
        arg1, arg2, arg3, arg4, 
        [item1, item2, item3, item4,
              item5, item6, item7, 
              item8, item9, item10,
], 
       arg6, key=spam, word=eggs, 
       extras=None, foo=bar,
)


 
-- 
Steven

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#50150

On 07/08/2013 08:02 AM, Steven D'Aprano wrote:
> On Mon, 08 Jul 2013 11:39:21 +0100, Joshua Landau wrote:
>
     <SNIP>
>
>> Or you can (be sane) and put it at no indentation:
>>
>> """
>> a_wonderful_set_of_things = {
>>      ...,
>>      not_missing_an_end_brace
>> }
>> """
>
> I consider that the least aesthetically pleasing, and also rather awkward:
>
>
> some_result = some_function(
>          arg1, arg2, arg3, arg4,
>          [item1, item2, item3, item4,
>                item5, item6, item7,
>                item8, item9, item10,
> ],
>         arg6, key=spam, word=eggs,
>         extras=None, foo=bar,
> )

or even better:

class  MyClass:
     def my_method(self):
         if self.flag:
             self.value.append(
                  arg1,
                  arg2,
                  arg3
)
             return self.value




-- 
DaveA

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#50153

On 8 July 2013 13:02, Steven D'Aprano
<steve+comp.lang.python@pearwood.info> wrote:
> On Mon, 08 Jul 2013 11:39:21 +0100, Joshua Landau wrote:
>  Imagine:
>>
>> """
>> a_wonderful_set_of_things = {
>>     bannanas_made_of_apples,
>>     chocolate_covered_horns,
>>     doors_that_slide,
>>     china_but_on_the_moon,
>>     buffalo_with_windy_hair,
>>     not_missing_an_end_brace
>> """¹
>>
>> Now, there are several places you can put the end brace. You can (be a
>> massive fool and) put it after the last item:
>>
>> """
>> a_wonderful_set_of_things = {
>>     ...,
>>     not_missing_an_end_brace}
>> """
>
> Well, call me a fool then, because when I have code that extends over
> *one* additional line, I prefer that:
>
>     raise ValueError(
>             "Some error message too long to fit on the above line")
>
> rather than:
>
>     raise ValueError(
>             "Some error message too long to fit on the above line"
>             )

Fool.

>> You can also (be a fool and) put it at the same *indentation*:
>>
>> """
>> a_wonderful_set_of_things = {
>>     ...,
>>     not_missing_an_end_brace
>>     }
>> """
>
> Call me a fool again, since I prefer this when there are more than one
> additional line. At least this time I'm in good company, since that's
> recommended by PEP 8.

Fool (less so, though).

>> Or you can (be sane) and put it at no indentation:
>>
>> """
>> a_wonderful_set_of_things = {
>>     ...,
>>     not_missing_an_end_brace
>> }
>> """
>
> I consider that the least aesthetically pleasing, and also rather awkward:
>
>
> some_result = some_function(
>         arg1, arg2, arg3, arg4,
>         [item1, item2, item3, item4,
>               item5, item6, item7,
>               item8, item9, item10,
> ],
>        arg6, key=spam, word=eggs,
>        extras=None, foo=bar,
> )

http://xkcd.com/605/

It was obvious¹ I was talking in context of my example. I used "no
indentation" because in that case "no indentation" was correct. If you
indent line #1, it follows that other lines might well be indented to
keep style consistent.

¹ I hope. I never suggested otherwise.

Since it's not too clear for you, my usage of fool was meant
pseudoironically as a subtle reminder that it's all subjective anyway,
but that I'm also still right.

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