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Groups > comp.lang.python > #75499

Re: Creating a 2s compliment hex string for negitive numbers

Date 2014-08-01 21:47 +0100
From MRAB <python@mrabarnett.plus.com>
Subject Re: Creating a 2s compliment hex string for negitive numbers
References <17160115-a77f-436a-837c-cd2039a7c53f@googlegroups.com>
Newsgroups comp.lang.python
Message-ID <mailman.12523.1406926051.18130.python-list@python.org> (permalink)

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On 2014-08-01 21:35, bSneddon wrote:
> I need to calculate an error correction code for an old protocol.
>
> I calculate the integer 4617 and want to code the 2s compliment in ASCII
> hex EDF7.  When issue the following.
>>>> hex(-4617)
> '-0x1209'
>
> Does anyone know a clean way to get to the desired results?   My ECC will always
> be 16 bit (4 nibble) hex number.
>
Use a bitwise AND:

 >>> hex(-4617 & 0xFFFF)
'0xedf7'

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Thread

Creating a 2s compliment hex string for negitive numbers bSneddon <w.g.sneddon@gmail.com> - 2014-08-01 13:35 -0700
  Re: Creating a 2s compliment hex string for negitive numbers MRAB <python@mrabarnett.plus.com> - 2014-08-01 21:47 +0100
    Re: Creating a 2s compliment hex string for negitive numbers bSneddon <w.g.sneddon@gmail.com> - 2014-08-01 14:25 -0700

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