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Re: Iteration, while loop, and for loop

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On 2016-06-28, Tim Chase <python.list@tim.thechases.com> wrote:
> On 2016-06-29 01:20, Steven D'Aprano wrote:
>> While loops are great for loops where you don't know how many
>> iterations there will be but you do know that you want to keep
>> going while some condition applies:
>> 
>> while there is still work to be done:
>>     do some more work
>
> I find this particularly the case when the thing being iterated over
> can be changed, such as a queue of things to process:
>
>   items = deque()
>   items.append(root_node)
>   while items:
>     item = items.popleft()
>     process(item)
>     items.extend(item.children)

Yep, I often do something similar when processing a block of data
bytes comprising a sequence of "things" of varying number of bytes.

    data = read_a_blob_of_bytes()
    while data:
        #figure out how long the first "thing" is
        len = <some expression typically involving the first few bytes of 'data'>  
        handle_thing(data[:len])
        data = data[len:]
> But then, if you wrap up your "while" loop as a generator that yields
> things, you can then use it in a "for" loop which seems to me like
> the Pythonic way to do things. :-)

Yea, I keep telling myself that, but I never actually do it.

-- 
Grant Edwards               grant.b.edwards        Yow! How do I get HOME?
                                  at               
                              gmail.com            

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Iteration, while loop, and for loop Elizabeth Weiss <cake240@gmail.com> - 2016-06-28 05:36 -0700
  Re: Iteration, while loop, and for loop Michael Selik <michael.selik@gmail.com> - 2016-06-28 13:15 +0000
    Re: Iteration, while loop, and for loop BartC <bc@freeuk.com> - 2016-06-28 14:29 +0100
      Re: Iteration, while loop, and for loop Michael Selik <michael.selik@gmail.com> - 2016-06-28 13:58 +0000
      Re: Iteration, while loop, and for loop Lawrence D’Oliveiro <lawrencedo99@gmail.com> - 2016-06-28 22:58 -0700
  Re: Iteration, while loop, and for loop BartC <bc@freeuk.com> - 2016-06-28 14:24 +0100
  RE: Iteration, while loop, and for loop "Joseph Lee" <joseph.lee22590@gmail.com> - 2016-06-28 06:26 -0700
  Re: Iteration, while loop, and for loop Jussi Piitulainen <jussi.piitulainen@helsinki.fi> - 2016-06-28 16:42 +0300
  Re: Iteration, while loop, and for loop Michael Selik <michael.selik@gmail.com> - 2016-06-28 13:51 +0000
  Re: Iteration, while loop, and for loop Steven D'Aprano <steve@pearwood.info> - 2016-06-29 01:20 +1000
    Re: Iteration, while loop, and for loop Jussi Piitulainen <jussi.piitulainen@helsinki.fi> - 2016-06-28 18:28 +0300
    Re: Iteration, while loop, and for loop Tim Chase <python.list@tim.thechases.com> - 2016-06-28 12:23 -0500
    Re: Iteration, while loop, and for loop Grant Edwards <grant.b.edwards@gmail.com> - 2016-06-28 17:58 +0000
    Re: Iteration, while loop, and for loop Ian Kelly <ian.g.kelly@gmail.com> - 2016-06-29 09:29 -0600
      Re: Iteration, while loop, and for loop Steven D'Aprano <steve@pearwood.info> - 2016-06-30 09:59 +1000
        Re: Iteration, while loop, and for loop Tim Chase <python.list@tim.thechases.com> - 2016-06-30 05:44 -0500
        Re: Iteration, while loop, and for loop Ian Kelly <ian.g.kelly@gmail.com> - 2016-06-30 07:04 -0600
        Re: Iteration, while loop, and for loop Ian Kelly <ian.g.kelly@gmail.com> - 2016-06-30 07:10 -0600
        Re: Iteration, while loop, and for loop jfong@ms4.hinet.net - 2016-06-30 19:12 -0700
  Re: Iteration, while loop, and for loop Veek M <vek.m1234@gmail.com> - 2016-10-27 14:35 +0530

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