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Re: Syntactic sugar for assignment statements: one value to multiple targets?

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Date Wed, 17 Aug 2011 03:11:36 +0100
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Subject Re: Syntactic sugar for assignment statements: one value to multiple targets?
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On 17/08/2011 01:14, gc wrote:
> On Aug 16, 4:39 pm, "Martin P. Hellwig"<martin.hell...@gmail.com>
> wrote:
>> On 03/08/2011 02:45, gc wrote:
>> <cut>
>>
>>> a,b,c,d,e = *dict()
>>
>>> where * in this context means something like "assign separately to
>>> all.
>
>> <snip>  . . . it has a certain code smell to it.<snip>
>> I would love to see an example where you would need such a construct.
>
> Perfectly reasonable request! Maybe there aren't as many cases when
> multiple variables need to be initialized to the same value as I think
> there are.
>
[snip]
As I see it, there are 2 issues:

1. Repeated evaluation of an expression: "dict()" would be evaluated as
many times as necessary. In other words, it's an unlimited generator.

2. Lazy unpacking: unpacking normally continues until the source is
exhausted, but here you want it to stop when the destination (the RHS)
is satisfied.

It just happens that in your use-case they are being used together.

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Thread

Syntactic sugar for assignment statements: one value to multiple targets? gc <gc1223@gmail.com> - 2011-08-02 18:45 -0700
  Re: Syntactic sugar for assignment statements: one value to multiple targets? Chris Angelico <rosuav@gmail.com> - 2011-08-03 03:09 +0100
  Re: Syntactic sugar for assignment statements: one value to multiple targets? Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2011-08-03 18:25 +1000
    Re: Syntactic sugar for assignment statements: one value to multiple targets? Tim Chase <python.list@tim.thechases.com> - 2011-08-03 06:15 -0500
    Re: Syntactic sugar for assignment statements: one value to multiple targets? Tim Chase <python.list@tim.thechases.com> - 2011-08-03 06:25 -0500
      Re: Syntactic sugar for assignment statements: one value to multiple targets? gc <gc1223@gmail.com> - 2011-08-16 12:50 -0700
  Re: Syntactic sugar for assignment statements: one value to multiple targets? Gregory Ewing <greg.ewing@canterbury.ac.nz> - 2011-08-03 20:29 +1200
  Re: Syntactic sugar for assignment statements: one value to multiple targets? "Martin P. Hellwig" <martin.hellwig@gmail.com> - 2011-08-16 21:39 +0100
    Re: Syntactic sugar for assignment statements: one value to multiple targets? gc <gc1223@gmail.com> - 2011-08-16 17:14 -0700
      Re: Syntactic sugar for assignment statements: one value to multiple targets? MRAB <python@mrabarnett.plus.com> - 2011-08-17 03:11 +0100
      Re: Syntactic sugar for assignment statements: one value to multiple targets? Chris Angelico <rosuav@gmail.com> - 2011-08-17 08:13 +0100
        Re: Syntactic sugar for assignment statements: one value to multiple targets? gc <gc1223@gmail.com> - 2011-08-17 02:26 -0700
          Re: Syntactic sugar for assignment statements: one value to multiple targets? Chris Angelico <rosuav@gmail.com> - 2011-08-17 10:45 +0100
            Re: Syntactic sugar for assignment statements: one value to multiple targets? gc <gc1223@gmail.com> - 2011-08-17 03:33 -0700
          Re: Syntactic sugar for assignment statements: one value to multiple targets? Terry Reedy <tjreedy@udel.edu> - 2011-08-17 12:12 -0400
          Re: Syntactic sugar for assignment statements: one value to multiple targets? MRAB <python@mrabarnett.plus.com> - 2011-08-17 17:55 +0100
          Re: Syntactic sugar for assignment statements: one value to multiple targets? Chris Angelico <rosuav@gmail.com> - 2011-08-17 18:25 +0100
          Re: Syntactic sugar for assignment statements: one value to multiple targets? "OKB (not okblacke)" <brenNOSPAMbarn@NObrenSPAMbarn.net> - 2011-08-17 19:13 +0000
      Re: Syntactic sugar for assignment statements: one value to multiple targets? Zero Piraeus <schesis@gmail.com> - 2011-08-17 16:07 -0400
  Re: Syntactic sugar for assignment statements: one value to multiple targets? Ethan Furman <ethan@stoneleaf.us> - 2011-08-17 12:52 -0700
  Re: Syntactic sugar for assignment statements: one value to multiple targets? John Pinner <funthyme@gmail.com> - 2011-08-18 02:26 -0700
  Re: Syntactic sugar for assignment statements: one value to multiple targets? Roy Smith <roy@panix.com> - 2011-08-18 09:13 -0400

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