[Python-ideas] Allow key='attribute_name' to various sorting functions

[João Bernardo]

It was something I did for fun, so I never had the time to add proper
documentation.
You can see the best examples to use by reading the doctests from __init__ .

BTW, It abuses a lot of Python 3 constructions, so you can't use Python 2.x



João Bernardo


2013/4/11 Ram Rachum <ram.rachum at gmail.com>

> Awesome module!
>
>
> On Fri, Apr 12, 2013 at 2:58 AM, João Bernardo <jbvsmo at gmail.com> wrote:
>
>> You can have something like that with this module I created:
>>      https://github.com/jbvsmo/funcbuilder
>>
>> from funcbuilder import f
>> sorted(entries, key=f.datetime_created)
>>
>>
>> Some features in this module are *very* experimental, but are also very
>> cool...
>>
>>
>> João Bernardo
>>
>>
>> 2013/4/11 Ram Rachum <ram.rachum at gmail.com>
>>
>>> Interesting!
>>>
>>>
>>> On Fri, Apr 12, 2013 at 2:33 AM, Haoyi Li <haoyi.sg at gmail.com> wrote:
>>>
>>>> A more generic and useful thing would be kind of what scala/groovy
>>>> have: shorthands for defining function literals:
>>>>
>>>> Groovy:
>>>> myList.sort{it.startTime}
>>>>
>>>> Scala:
>>>> myList.sort(_.startTime)
>>>>
>>>> Where "_.startTime" and "it.startTime" are shorthand for "x =>
>>>> x.startTime" or python's "lambda x: x.startTime". You could probably get
>>>> something similar in python:
>>>>
>>>> sorted(entries, key = x.datetime_created)
>>>>
>>>> if you did some magic with x to make looking up an attribute return a
>>>> lambda that returns that attribute of its argument.
>>>>
>>>> -Haoyi
>>>>
>>>>
>>>>
>>>> On Thu, Apr 11, 2013 at 7:05 PM, Oscar Benjamin <
>>>> oscar.j.benjamin at gmail.com> wrote:
>>>>
>>>>> On 11 April 2013 23:52, Ram Rachum <ram.rachum at gmail.com> wrote:
>>>>> > On Friday, April 12, 2013 1:35:20 AM UTC+3, Carl Meyer wrote:
>>>>> >>
>>>>> >> On 04/11/2013 04:24 PM, Ram Rachum wrote:
>>>>> >> > I often want to sort objects by an attribute. It's cumbersome to
>>>>> do
>>>>> >> > this:
>>>>> >> >
>>>>> >> >     sorted(entries, key=lambda entry: entry.datetime_created)
>>>>> >> >
>>>>> >> > Why not allow this instead:
>>>>> >> >
>>>>> >> >     sorted(entries, key='datetime_created')
>>>>> >>
>>>>> >>     from operator import attrgetter
>>>>> >>     sorted(entries, key=attrgetter('datetime_created'))
>>>>> >>
>>>>> >> You can alias attrgetter to an even shorter name if you like.
>>>>> >
>>>>> > That's still cumbersome in my opinion.
>>>>>
>>>>> I don't think it's that cumbersome. Leaving aside the import line
>>>>> you're only having to specify two things for your key function: that
>>>>> it's an attribute (attrgetter) and the name of the attribute
>>>>> ('datetime_created'). It's not possible for this to be any more
>>>>> succinct without using special case implicit rules which are generally
>>>>> a bad thing. I like the fact that the API for the sorted function is
>>>>> so simple I can remember all of its arguments and exactly what they do
>>>>> without ever needing to look it up.
>>>>>
>>>>>
>>>>> Oscar
>>>>> _______________________________________________
>>>>> Python-ideas mailing list
>>>>> Python-ideas at python.org
>>>>> http://mail.python.org/mailman/listinfo/python-ideas
>>>>>
>>>>
>>>>
>>>
>>> _______________________________________________
>>> Python-ideas mailing list
>>> Python-ideas at python.org
>>> http://mail.python.org/mailman/listinfo/python-ideas
>>>
>>>
>>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mail.python.org/pipermail/python-ideas/attachments/20130411/8cdf3b3f/attachment.html>