swapping numeric items in a list
Hi, I simplify my problem like below To convert list aa = [0x12, 0x34, 0x56, 0x78] into [0x34, 0x12, 0x78, 0x56] How to do it fast? My real list is huge. Thanks a lot. Jason -- http://mail.python.org/mailman/listinfo/python-list
Re: swapping numeric items in a list
Thank you all guys for the help. Guess I'm gonna pick bearophile's way. It's
fast, neat, and easy to read.
array.byteswap() won't work for me easily. I tried this before my 1st post.
I defined
aa = array('H', [0x12, 0x34, 0x56, 0x78])
Then did byteswap aa.byteswap(). The result was
array('H', [0x1200, 0x3400, 0x5600, 0x7800])
You can see it byteswapped within each item.
Jason
"Marc 'BlackJack' Rintsch" <[EMAIL PROTECTED]> wrote in message
news:[EMAIL PROTECTED]
> In <[EMAIL PROTECTED]>, Jiang Nutao
> wrote:
>
>> To convert list
>> aa = [0x12, 0x34, 0x56, 0x78]
>> into
>> [0x34, 0x12, 0x78, 0x56]
>>
>> How to do it fast? My real list is huge.
>
> Use the `array` module and the `array.byteswap()` method.
>
> Ciao,
> Marc 'BlackJack' Rintsch
> --
> http://mail.python.org/mailman/listinfo/python-list
>
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Re: swapping numeric items in a list
This is what I got in the debugger:
(Pdb) aa=array('b', [126, 55, 71, 112])
(Pdb) aa
array('b', [126, 55, 71, 112])
(Pdb) aa.byteswap()
(Pdb) aa
array('b', [126, 55, 71, 112])
- Original Message -
From: "Gabriel Genellina" <[EMAIL PROTECTED]>
To: "Jiang Nutao" <[EMAIL PROTECTED]>
Cc:
Sent: Wednesday, August 23, 2006 11:28 AM
Subject: Re: swapping numeric items in a list
> At Wednesday 23/8/2006 14:44, Jiang Nutao wrote:
>
>>array.byteswap() won't work for me easily. I tried this before my 1st
>>post.
>>I defined
>>
>> aa = array('H', [0x12, 0x34, 0x56, 0x78])
>>
>>Then did byteswap aa.byteswap(). The result was
>>
>> array('H', [0x1200, 0x3400, 0x5600, 0x7800])
>>
>>You can see it byteswapped within each item.
>
> Use array('b') or 'B'. 'H' are two-byes integers.
>
>
>
> Gabriel Genellina
> Softlab SRL
>
>
>
>
> __
> Preguntá. Respondé. Descubrí.
> Todo lo que querías saber, y lo que ni imaginabas,
> está en Yahoo! Respuestas (Beta).
> ¡Probalo ya! http://www.yahoo.com.ar/respuestas
>
>
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Re: swapping numeric items in a list
Thanks. But the thing I need to swap is [0x12, 0x34, 0x56, 0x78], not
[0x1234, 0x5678].
- Original Message -
From: "Gabriel Genellina" <[EMAIL PROTECTED]>
To: "Jiang Nutao" <[EMAIL PROTECTED]>
Cc: "Gabriel Genellina" <[EMAIL PROTECTED]>;
Sent: Wednesday, August 23, 2006 12:19 PM
Subject: Re: swapping numeric items in a list
> At Wednesday 23/8/2006 15:32, Jiang Nutao wrote:
>
>>This is what I got in the debugger:
>>
>>(Pdb) aa=array('b', [126, 55, 71, 112])
>>(Pdb) aa
>>array('b', [126, 55, 71, 112])
>>(Pdb) aa.byteswap()
>>(Pdb) aa
>>array('b', [126, 55, 71, 112])
>
> Oh, sorry, to swap by two bytes "H" was the right typecode. But your input
> array should be:
>>>> aa = array('H', [0x1234, 0x5678])
> which should give:
> array('H', [0x3412, 0x7856])
>
>
>
> Gabriel Genellina
> Softlab SRL
>
>
>
>
> __
> Preguntá. Respondé. Descubrí.
> Todo lo que querías saber, y lo que ni imaginabas,
> está en Yahoo! Respuestas (Beta).
> ¡Probalo ya! http://www.yahoo.com.ar/respuestas
>
>
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