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Re: [newbie] A question about lists and strings

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On 08/10/2012 06:37 AM, Chris Angelico wrote:
> On Fri, Aug 10, 2012 at 8:12 PM, Mok-Kong Shen
> <mok-kong.shen@t-online.de> wrote:
>> Thanks for the explanation of the output obtained. But this means
>> nonetheless that parameters of types lists and strings are dealt with
>> in "inherently" (semantically) different ways by Python, right?
> It's nothing to do with parameters, but yes, lists are mutable and
> strings are immutable. A tuple will behave the same way a string does:
>
>>>> a
> (1, 2, 3, 4)
>>>> b=a
>>>> a+=5,    # note that "5," is a one-element tuple
>>>> a
> (1, 2, 3, 4, 5)
>>>> b
> (1, 2, 3, 4)
>
>
> By the way:
>
> On Fri, Aug 10, 2012 at 8:07 PM, Dave Angel <d@davea.name> wrote:
>> But if you said  c=651 and d=651, you'd have two
>> objects, and the two names would be bound to different objects, with
>> different ids.
> To be more accurate, you *may* have two different objects. It's
> possible for things to be optimized (eg with small numbers, or with
> constants compiled at the same time).
>
> ChrisA

You're right, of course.  But I picked the value of 650+ deliberately,
as I believe CPython doesn't currently optimize ints over 256.



-- 

DaveA

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[newbie] A question about lists and strings Mok-Kong Shen <mok-kong.shen@t-online.de> - 2012-08-10 11:19 +0200
  Re: [newbie] A question about lists and strings Roman Vashkevich <vashkevichrb@gmail.com> - 2012-08-10 13:28 +0400
  Re: [newbie] A question about lists and strings Roman Vashkevich <vashkevichrb@gmail.com> - 2012-08-10 13:48 +0400
    Re: [newbie] A question about lists and strings Mok-Kong Shen <mok-kong.shen@t-online.de> - 2012-08-10 12:12 +0200
      Re: [newbie] A question about lists and strings Chris Angelico <rosuav@gmail.com> - 2012-08-10 20:37 +1000
      Re: [newbie] A question about lists and strings Dave Angel <d@davea.name> - 2012-08-10 06:37 -0400
      Re: [newbie] A question about lists and strings Roman Vashkevich <vashkevichrb@gmail.com> - 2012-08-10 14:56 +0400
        Re: [newbie] A question about lists and strings Mok-Kong Shen <mok-kong.shen@t-online.de> - 2012-08-10 13:08 +0200
      Re: [newbie] A question about lists and strings Dave Angel <d@davea.name> - 2012-08-10 06:56 -0400
      Re: [newbie] A question about lists and strings Chris Angelico <rosuav@gmail.com> - 2012-08-10 21:00 +1000
      Re: [newbie] A question about lists and strings Roman Vashkevich <vashkevichrb@gmail.com> - 2012-08-10 15:06 +0400
  Re: [newbie] A question about lists and strings Peter Otten <__peter__@web.de> - 2012-08-10 11:59 +0200
    Re: [newbie] A question about lists and strings Rotwang <sg552@hotmail.co.uk> - 2012-08-10 16:12 +0100
  Re: [newbie] A question about lists and strings Dave Angel <d@davea.name> - 2012-08-10 06:07 -0400
    Re: [newbie] A question about lists and strings Mok-Kong Shen <mok-kong.shen@t-online.de> - 2012-08-10 12:31 +0200
      Re: [newbie] A question about lists and strings Chris Angelico <rosuav@gmail.com> - 2012-08-10 20:40 +1000
        Re: [newbie] A question about lists and strings Mok-Kong Shen <mok-kong.shen@t-online.de> - 2012-08-10 12:48 +0200
          Re: [newbie] A question about lists and strings Dave Angel <d@davea.name> - 2012-08-10 06:58 -0400
      Re: [newbie] A question about lists and strings Dave Angel <d@davea.name> - 2012-08-10 06:53 -0400

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