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Re: what would be the regular expression for null byte present in a string

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  Re: what would be the regular expression for null byte present in a string Peter Otten <__peter__@web.de> - 2015-01-13 15:41 +0100
    Re: what would be the regular expression for null byte present in a string Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2015-01-14 14:52 +0100
      Re: what would be the regular expression for null byte present in a string Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2015-01-14 15:11 +0100

#83698 — Re: what would be the regular expression for null byte present in a string

Shambhu Rajak wrote:

> I have a string that I get as an output of a command as:
> 
'\x01\x00\x00\x00\x00\x00\x00\x00\x0c\x00\x00\x0010232ae8944a\x02\x00\x00\x00\x00\x00\x00\x00\n'
> 
> I want to fetch '10232ae8944a' from the above string.
> 
> I want to find a re pattern that could replace all the \x01..\x0z to be
> replace by empty string '',  so that I can get the desired portion of
> string
> 
> Can anyone help me with a working regex for it.

I think you want the str.tranlate() method rather than a regex. 

Assuming you are using Python 2:

>>> delenda = "".join(map(chr, range(32)))
>>> identity = "".join(map(chr, range(256)))
>>> 
'\x01\x00\x00\x00\x00\x00\x00\x00\x0c\x00\x00\x0010232ae8944a\x02\x00\x00\x00\x00\x00\x00\x00\n'.translate(identity, 
delenda)
'10232ae8944a'

With Python3:

>>> mapping = dict.fromkeys(range(32))
>>> 
'\x01\x00\x00\x00\x00\x00\x00\x00\x0c\x00\x00\x0010232ae8944a\x02\x00\x00\x00\x00\x00\x00\x00\n'.translate(mapping)
'10232ae8944a'

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#83755

Peter Otten wrote:

> Shambhu Rajak wrote:
>> I have a string that I get as an output of a command as:
>> 
> 
'\x01\x00\x00\x00\x00\x00\x00\x00\x0c\x00\x00\x0010232ae8944a\x02\x00\x00\x00\x00\x00\x00\x00\n'
>> 
>> I want to fetch '10232ae8944a' from the above string.
>> 
>> I want to find a re pattern that could replace all the \x01..\x0z to be
>> replace by empty string '',  so that I can get the desired portion of
>> string
>> 
>> Can anyone help me with a working regex for it.
> 
> I think you want the str.tranlate() method rather than a regex.

Another possibility, but given the length of the list probably not the most 
efficient one.  Aside from re and this one, here is another (tested with 
Python 3.4.2):

  filtered = ''.join(filter(lambda ch: ord(ch) > 0x0f, s))

-- 
PointedEars

Twitter: @PointedEars2
Please do not cc me. / Bitte keine Kopien per E-Mail.

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#83756

Thomas 'PointedEars' Lahn wrote:

> Peter Otten wrote:
>> Shambhu Rajak wrote:
>>> I want to find a re pattern that could replace all the \x01..\x0z to be
>>> replace by empty string '',  so that I can get the desired portion of
>>> string
>>> 
>>> Can anyone help me with a working regex for it.
>> 
>> I think you want the str.tranlate() method rather than a regex.
> 
> Another possibility, but given the length of the list probably not the
> most efficient one.  Aside from re and this one, here is another (tested
> with Python 3.4.2):
> 
>   filtered = ''.join(filter(lambda ch: ord(ch) > 0x0f, s))

  filtered = ''.join(filter(lambda ch: ch > "\x0f", s))

-- 
PointedEars

Twitter: @PointedEars2
Please do not cc me. / Bitte keine Kopien per E-Mail.

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