[Python-Dev] PEP 8 modernisation

[Ronald Oussoren]

On 1 Aug, 2013, at 17:03, Alexander Shorin <kxepal at gmail.com> wrote:

> ...and, if so, why lambda's?(: Without backward compatibility point I
> see that they are getting "unofficially" deprecated and their usage is
> dishonoured.

They are still usefull for simple functions that you use in one place,
such as the key argument to sorted. By the time you assign a name to the function
and give it unittests you may as well use a def-statement and let the
function know it its own name.  

Ronald

> 
> --
> ,,,^..^,,,
> 
> 
> On Thu, Aug 1, 2013 at 6:53 PM, Ronald Oussoren <ronaldoussoren at mac.com> wrote:
>> 
>> On 1 Aug, 2013, at 16:48, Alexander Shorin <kxepal at gmail.com> wrote:
>> 
>>> Hi Ronald,
>>> 
>>> I understand this, but I'm a bit confused about fate of lambdas with
>>> such guideline since I see no more reasons to use them with p.9
>>> statement: long lines, code duplicate, no mock and well tests etc. -
>>> all these problems could be solved with assigning lambda to some name,
>>> but now they are looks useless (or useful only for very trivial cases)
>> 
>> That sounds about right :-)
>> 
>> Note that:
>> 
>>   f = lambda x: x ** 2
>> 
>> And:
>> 
>>   def f(x): return x ** 2
>> 
>> Are functionally equivalent and use the same byte code. The only differences
>> are that the lambda saves two characters in typing, and the "def" variant has
>> a more useful value in its __name__ attribute.
>> 
>> IMHO The lambda variant also looks uglier (even with the def variant on a single line).
>> 
>> Ronald
>> 
>>> --
>>> ,,,^..^,,,
>>> 
>>> 
>>> On Thu, Aug 1, 2013 at 6:41 PM, Ronald Oussoren <ronaldoussoren at mac.com> wrote:
>>>> 
>>>> On 1 Aug, 2013, at 16:34, Alexander Shorin <kxepal at gmail.com> wrote:
>>>> 
>>>>> Hi Nick,
>>>>> 
>>>>> On Thu, Aug 1, 2013 at 4:44 PM, Nick Coghlan <ncoghlan at gmail.com> wrote:
>>>>>> 9. Explicit guideline not to assign lambdas to names (use def, that's
>>>>>> what it's for)
>>>>> 
>>>>> Even for propose to fit chars-per-line limit and/or to remove
>>>>> duplicates (especially for sorted groupby case)?
>>>> 
>>>> When you do "name = lambda ..." you've created a named function, when you
>>>> do that your better of using def statement for the reasons Nick mentioned
>>>> in the PEP.
>>>> 
>>>> Ronald
>>>> 
>>>>> 
>>>>> --
>>>>> ,,,^..^,,,
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>>>> 
>>