Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > comp.lang.python > #32302

Re: attaching names to subexpressions

Show key headers only | View raw

On Sat, Oct 27, 2012 at 8:49 PM, Steven D'Aprano
<steve+comp.lang.python@pearwood.info> wrote:
> On Sat, 27 Oct 2012 15:03:38 +0200, Gelonida N wrote:
>
>> line = complex_exression
>> while line:
>>      do something with(line)
>>      line = complex_expression
>>
>> violates clearly the DRY principle  and the risk to change one line but
>> not the other is high.
-- snip --
> while True:
>      line = function(x, y, z)
>      if not line:
>          break
>      big ugly block of code
>
>
> There you go. DRY.

>> The 'canonical way'
>> while True:
>>      line = complex_expression
>>      if not line:
>>          break
>>      do_something_with(line)
>>
>> avoids this problem, but I was never really convinced about the beauty /
>> readbility of this construct.
>>
>> In
>> my opinion I shouldn't be obliged to read any of the indented lines of
>> the while statement on a first 'visual' pass through somebody elses code
>> and still be able to see what the loop iterates through.
>
> Fine. Then write your code as:
>
> line = function(x, y, z)
> while line:
>      do something with(line)
>      line = function(x, y, z)
>

We have a problem, and two solutions. Solution 1 has downside A, and
solution 2 has downside B. If he complains about downside A, you say,
well, use solution 2. If he complains about downside B, you say, well,
use solution 1.

What if he wants to avoid both downsides A and B? What solution does
he use then?

-- Devin

Back to comp.lang.python | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread

Thread

attaching names to subexpressions Steve Howell <showell30@yahoo.com> - 2012-10-26 19:42 -0700
  Re: attaching names to subexpressions Gelonida N <gelonida@gmail.com> - 2012-10-27 15:03 +0200
    Re: attaching names to subexpressions Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2012-10-28 00:49 +0000
      Re: attaching names to subexpressions rusi <rustompmody@gmail.com> - 2012-10-27 18:57 -0700
      Re: attaching names to subexpressions Devin Jeanpierre <jeanpierreda@gmail.com> - 2012-10-28 01:57 -0400
        Re: attaching names to subexpressions Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2012-10-28 06:59 +0000
          Re: attaching names to subexpressions Devin Jeanpierre <jeanpierreda@gmail.com> - 2012-10-28 04:12 -0400
        Re: attaching names to subexpressions Neil Cerutti <neilc@norwich.edu> - 2012-10-29 11:53 +0000
      Re: attaching names to subexpressions Chris Angelico <rosuav@gmail.com> - 2012-10-28 17:01 +1100
      Re: attaching names to subexpressions "F.R." <anthra.norell@bluewin.ch> - 2012-10-28 08:12 +0100
      Re: attaching names to subexpressions Chris Angelico <rosuav@gmail.com> - 2012-10-28 21:44 +1100

csiph-web