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Re: Is there a function that applies list of functions to a value?

From alex23 <wuwei23@gmail.com>
Newsgroups comp.lang.python
Subject Re: Is there a function that applies list of functions to a value?
Date 2013-08-30 16:36 +1000
Organization A noiseless patient Spider
Message-ID <kvpehq$b6g$1@dont-email.me> (permalink)
References <aa168508-c469-4b02-9dc1-e0efd023d52b@googlegroups.com> <cf0fa304-1965-4173-89cd-6167a3427439@googlegroups.com> <7867a7cb-e419-4f2e-8d3d-30862de93014@googlegroups.com>

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On 30/08/2013 4:17 PM, fp2161@gmail.com wrote:
> On Wednesday, August 28, 2013 8:50:53 PM UTC+2, Josh English wrote:
>> def compose(*funcs):
>>      for func in funcs:
>>          if not callable(func):
>>              raise ValueError('Must pass callable functions')

> Imho still, the ValueError you are raising is not that important in this context, it would raise an Error anyway.

The main advantage with Josh's approach is that it fails at the point of 
composition, not when the composed function is first used.  It'd be even 
more useful if it aggregated a list of the failing functions and 
returned their names as part of the error.

Personally, I'd go with an assertion:

     assert all(map(callable, funcs)), "Must pass callable functions"

I find that it makes it more obvious that this is part of the function 
contract rather than the actual body.

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Thread

Is there a function that applies list of functions to a value? AdamKal <adamkalinski@gmail.com> - 2013-08-28 05:52 -0700
  Re: Is there a function that applies list of functions to a value? Jussi Piitulainen <jpiitula@ling.helsinki.fi> - 2013-08-28 16:10 +0300
    Re: Is there a function that applies list of functions to a value? fp2161@gmail.com - 2013-08-29 15:48 -0700
  Re: Is there a function that applies list of functions to a value? Tim Chase <python.list@tim.thechases.com> - 2013-08-28 08:11 -0500
    Re: Is there a function that applies list of functions to a value? Jussi Piitulainen <jpiitula@ling.helsinki.fi> - 2013-08-28 16:19 +0300
    Re: Is there a function that applies list of functions to a value? AdamKal <adamkalinski@gmail.com> - 2013-08-28 06:23 -0700
      Re: Is there a function that applies list of functions to a value? Chris Angelico <rosuav@gmail.com> - 2013-08-28 23:26 +1000
      Re: Is there a function that applies list of functions to a value? Tim Chase <python.list@tim.thechases.com> - 2013-08-28 08:43 -0500
        Re: Is there a function that applies list of functions to a value? AdamKal <adamkalinski@gmail.com> - 2013-08-28 06:50 -0700
  Re: Is there a function that applies list of functions to a value? ishish <ishish@domhain.de> - 2013-08-28 14:17 +0100
  Re: Is there a function that applies list of functions to a value? Thomas Rachel <nutznetz-0c1b6768-bfa9-48d5-a470-7603bd3aa915@spamschutz.glglgl.de> - 2013-08-28 15:09 +0200
  Re: Is there a function that applies list of functions to a value? Josh English <Joshua.R.English@gmail.com> - 2013-08-28 11:50 -0700
    Re: Is there a function that applies list of functions to a value? fp2161@gmail.com - 2013-08-29 23:17 -0700
      Re: Is there a function that applies list of functions to a value? alex23 <wuwei23@gmail.com> - 2013-08-30 16:36 +1000
        Re: Is there a function that applies list of functions to a value? Fabrice Pombet <fp2161@gmail.com> - 2013-08-30 01:11 -0700
  Re: Is there a function that applies list of functions to a value? fp2161@gmail.com - 2013-08-29 13:50 -0700
    Re: Is there a function that applies list of functions to a value? Chris Angelico <rosuav@gmail.com> - 2013-08-30 07:05 +1000
      Re: Is there a function that applies list of functions to a value? fp2161@gmail.com - 2013-08-29 14:27 -0700
        Re: Is there a function that applies list of functions to a value? Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-08-30 02:18 +0000
        Re: Is there a function that applies list of functions to a value? Chris Angelico <rosuav@gmail.com> - 2013-08-30 07:35 +1000
          Re: Is there a function that applies list of functions to a value? fp2161@gmail.com - 2013-08-29 23:14 -0700
            Re: Is there a function that applies list of functions to a value? alex23 <wuwei23@gmail.com> - 2013-08-30 16:23 +1000
              Re: Is there a function that applies list of functions to a value? Fabrice Pombet <fp2161@gmail.com> - 2013-08-30 01:06 -0700
      Re: Is there a function that applies list of functions to a value? fp2161@gmail.com - 2013-08-29 14:48 -0700
        Re: Is there a function that applies list of functions to a value? Terry Reedy <tjreedy@udel.edu> - 2013-08-30 00:38 -0400
    Re: Is there a function that applies list of functions to a value? Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-08-30 02:09 +0000
      Re: Is there a function that applies list of functions to a value? fp2161@gmail.com - 2013-08-29 23:06 -0700

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