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

Groups > comp.lang.python > #53296

Re: semicolon at end of python's statements

Show all headers | View raw

Op 30-08-13 12:53, Roy Smith schreef:
> In article <mailman.385.1377858745.19984.python-list@python.org>,
>  Fábio Santos <fabiosantosart@gmail.com> wrote:
> 
>> On 29 Aug 2013 23:20, "Ben Finney" <ben+python@benfinney.id.au> wrote:
>>>
>>> Fábio Santos <fabiosantosart@gmail.com> writes:
>>>
>>>> It is a shame that this is not possible in python. for..if exists in
>>>> comprehensions and not in regular loops but that would be nice
>>>> sometimes.
>>>
>>> So you use it in a generator expression, and iterate over the generator:
>>>
>>>     for foo in (spam for spam in sequence if predicate(spam)):
>>>         process(spam)
>>>
>>> That way, there's no need for new syntax.
>>
>> The problem I have with that strategy is that it is repetitive and hinders
>> readability. You wrote "for" and "in" twice, and spam (a pretty useless
>> intermediate variable) thrice! While it does its job, it hides the true
>> intent for filtering beneath a lot of (pun intended) spam. The "if"
>> particle is nigh undetectable there.
>>
>> To get around this, I often declare a generator. But I still find it a bit
>> awkward to have to look up the definition elsewhere, and to waste lines
>> over something so simple.
>>
>> I can't say I understand why we don't merge the for loops' syntax with the
>> comprehension syntax. Even after following the for..while discussion.
> 
> +1 on loop comprehensions, for all the reasons Fábios states.

Maybe python should just allow more than one control structure on one
line and then considers the end of the suite the end of both controls.
In that case we could just write the following:

  for a in lst: if a % 2:
      treat a
      process a some more
  after loop things.

It technically is not loop comprehension but just nested controls but
by allowing them on the same line it looks close enough like loop
comprehension.

Plus if people have a problem that would best be solved by a while loop
comprehension that would be just as easy.

-- 
Antoon Pardon

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

Thread

Re: semicolon at end of python's statements "Sam Fourman Jr." <sfourman@gmail.com> - 2013-08-28 22:10 -0400
  Re: semicolon at end of python's statements Alister <alister.ware@ntlworld.com> - 2013-08-29 09:39 +0000
    Re: semicolon at end of python's statements Chris Angelico <rosuav@gmail.com> - 2013-08-29 19:52 +1000
    Re: semicolon at end of python's statements Fábio Santos <fabiosantosart@gmail.com> - 2013-08-29 11:02 +0100
    Re: semicolon at end of python's statements Ben Finney <ben+python@benfinney.id.au> - 2013-08-30 08:17 +1000
    Re: semicolon at end of python's statements Chris Angelico <rosuav@gmail.com> - 2013-08-30 08:50 +1000
    Re: semicolon at end of python's statements Ben Finney <ben+python@benfinney.id.au> - 2013-08-30 14:55 +1000
    Re: semicolon at end of python's statements Antoon Pardon <antoon.pardon@rece.vub.ac.be> - 2013-08-30 09:15 +0200
    Re: semicolon at end of python's statements Chris Angelico <rosuav@gmail.com> - 2013-08-30 17:25 +1000
    Re: semicolon at end of python's statements Antoon Pardon <antoon.pardon@rece.vub.ac.be> - 2013-08-30 09:48 +0200
    Re: semicolon at end of python's statements Fábio Santos <fabiosantosart@gmail.com> - 2013-08-30 11:32 +0100
      Re: semicolon at end of python's statements Roy Smith <roy@panix.com> - 2013-08-30 06:53 -0400
        Re: semicolon at end of python's statements Antoon Pardon <antoon.pardon@rece.vub.ac.be> - 2013-08-30 16:14 +0200
        Re: semicolon at end of python's statements Chris Angelico <rosuav@gmail.com> - 2013-08-31 08:18 +1000
      Re: semicolon at end of python's statements Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-08-31 00:09 +0000
        Re: semicolon at end of python's statements Terry Reedy <tjreedy@udel.edu> - 2013-08-31 01:03 -0400
        Re: semicolon at end of python's statements Jussi Piitulainen <jpiitula@ling.helsinki.fi> - 2013-08-31 10:47 +0300
          Re: semicolon at end of python's statements Paul Rudin <paul.nospam@rudin.co.uk> - 2013-08-31 09:00 +0100
            Re: semicolon at end of python's statements Jussi Piitulainen <jpiitula@ling.helsinki.fi> - 2013-08-31 13:28 +0300
            Re: semicolon at end of python's statements Grant Edwards <invalid@invalid.invalid> - 2013-09-02 14:20 +0000
              Re: semicolon at end of python's statements Tim Chase <python.list@tim.thechases.com> - 2013-09-02 09:45 -0500
                Re: semicolon at end of python's statements Roy Smith <roy@panix.com> - 2013-09-02 10:47 -0400
                Re: semicolon at end of python's statements Tim Chase <python.list@tim.thechases.com> - 2013-09-02 12:58 -0500
                Re: semicolon at end of python's statements Chris Angelico <rosuav@gmail.com> - 2013-09-03 07:07 +1000
        Re: semicolon at end of python's statements Antoon Pardon <antoon.pardon@rece.vub.ac.be> - 2013-09-01 19:58 +0200
        Re: semicolon at end of python's statements Antoon Pardon <antoon.pardon@rece.vub.ac.be> - 2013-09-01 21:58 +0200
          Re: semicolon at end of python's statements Steven D'Aprano <steve@pearwood.info> - 2013-09-02 08:05 +0000
            Re: semicolon at end of python's statements Antoon Pardon <antoon.pardon@rece.vub.ac.be> - 2013-09-02 11:45 +0200
            Re: semicolon at end of python's statements Fábio Santos <fabiosantosart@gmail.com> - 2013-09-02 11:42 +0100
            Re: semicolon at end of python's statements Antoon Pardon <antoon.pardon@rece.vub.ac.be> - 2013-09-02 12:58 +0200
            Re: semicolon at end of python's statements "albert visser" <albert.visser@gmail.com> - 2013-09-02 19:44 +0200
              Re: semicolon at end of python's statements Roy Smith <roy@panix.com> - 2013-09-02 13:53 -0400
                Re: semicolon at end of python's statements Neil Cerutti <neilc@norwich.edu> - 2013-09-03 17:15 +0000
                Re: semicolon at end of python's statements Neil Cerutti <neilc@norwich.edu> - 2013-09-03 20:00 +0000
            Re: semicolon at end of python's statements Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2013-09-02 17:24 -0400
        Re: semicolon at end of python's statements MRAB <python@mrabarnett.plus.com> - 2013-09-02 00:30 +0100
        Re: semicolon at end of python's statements Antoon Pardon <antoon.pardon@rece.vub.ac.be> - 2013-09-02 10:29 +0200
          Re: semicolon at end of python's statements Steven D'Aprano <steve@pearwood.info> - 2013-09-02 09:52 +0000
            Re: semicolon at end of python's statements Chris Angelico <rosuav@gmail.com> - 2013-09-02 20:14 +1000
              Re: semicolon at end of python's statements Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-09-02 14:57 +0000
            Re: semicolon at end of python's statements Antoon Pardon <antoon.pardon@rece.vub.ac.be> - 2013-09-02 12:52 +0200
            Re: semicolon at end of python's statements Modulok <modulok@gmail.com> - 2013-09-02 17:17 -0600
              Re: semicolon at end of python's statements Roy Smith <roy@panix.com> - 2013-09-02 19:54 -0400
                Re: semicolon at end of python's statements Modulok <modulok@gmail.com> - 2013-09-02 18:56 -0600

csiph-web