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Date: Fri, 10 Aug 2012 06:37:26 -0400
From: Dave Angel <d@davea.name>
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To: Mok-Kong Shen <mok-kong.shen@t-online.de>
Subject: Re: [newbie] A question about lists and strings
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On 08/10/2012 06:12 AM, Mok-Kong Shen wrote:
> Am 10.08.2012 11:48, schrieb Roman Vashkevich:
>> [snip]
> >The function .... It takes list by reference and creates a new local
> > str. When it's called with listb and strb arguments, listb is passed
> > by reference and mutated. A string "sss" is concatenated with an
> > empty local str. Nothing more happens. Since local str is not
> > returned by xx(), it can not be expected to be printed out in the
> > statement that follows. What is printed out in the print statement is
> > the mutated listb and the global strb.
>
> 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?
>
> M. K. Shen
>

Nothing to do with parameters.  Lists are mutable, and strings are
immutable, so += behaves differently.



-- 

DaveA