Re: expandtabs acts unexpectedly

2009-08-19 Thread Peter Brett 
digisat...@gmail.com digisat...@gmail.com writes:

 Python 2.6.2 (release26-maint, Apr 19 2009, 01:56:41)
 [GCC 4.3.3] on linux2
 Type help, copyright, credits or license for more information.
 ' test\ttest'.expandtabs(4)
 ' test   test'
 'test \ttest'.expandtabs(4)
 'testtest'

 1st example: expect returning 4 spaces between 'test', 3 spaces
 returned
 2nd example: expect returning 5 spaces between 'test', 4 spaces
 returned

 Is it a bug or something, please advice.

Consider where the 4-space tabstops are relative to those strings:

 test   test
testtest
^   ^   ^

So no, it's not a bug.

If you just want to replace the tab characters by spaces, use:

test\ttest.replace(\t, )
  ' testtest'
   test \ttest.replace(\t, )
  'test test'

HTH,

   Peter

-- 
Peter Brett pe...@peter-b.co.uk
Remote Sensing Research Group
Surrey Space Centre
-- 
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Re: Extract the numeric and alphabetic part from an alphanumeric string

2009-08-03 Thread Peter Brett 
Sandhya Prabhakaran sandhyaprabhaka...@gmail.com writes:

 Hi,

 I have a string as str='123ACTGAAC'.

 I need to extract the numeric part from the alphabetic part which I
 did using
numer=re.findall(r'\d+',str)
numer
 123

 To get the alphabetic part, I could do
alpha=str.replace('123','')
alpha
 ACTGAAC
 But when I give
alpha=str.replace(numer,'')
 Traceback (most recent call last):
   File stdin, line 1, in module
 TypeError: expected a character buffer object

 How do I blank out the initial numeric part so as to get just the
 alphabetic part. The string is always in the same format.

Firstly, you really should read the Regular Expression HOWTO:

  http://docs.python.org/howto/regex.html#regex-howto

Secondly, is this what you wanted to do?

   p = re.compile(r'^\d+')
   p.sub('', '123ACTGAAC')
  'ACTGAAC'

Regards,

   Peter

-- 
Peter Brett pe...@peter-b.co.uk
Remote Sensing Research Group
Surrey Space Centre
-- 
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Re: Regexp problem

2009-07-30 Thread Peter Brett 
Marcus Wanner marc...@cox.net writes:

 On 7/30/2009 9:32 AM, Beldar wrote:
 On 30 jul, 15:07, MRAB pyt...@mrabarnett.plus.com wrote:
 Beldar wrote:
 Hi there!
 I have a problem and i'm not very good at regular expressions.
 I have a text like lalala lalala tiruri beldar-is-listening tiruri
 lalala I need a regexp to get the 'beldar' part, the format is
 'something-is-listening', i need to get the something part, use it in
 my code, and then replace the whole 'something-is-listening' for
 another string.
 \w+ will match a word and enclosing it in (...) will capture what was
 matched:

  m = re.search(r(\w+)-is-listening, text)
  print Captured '%s' % m.group(1)
  print Matched from %d to %d % (m.start(), m.end())

 Ok, thank you all, it was very helpful!
 Wow, I really need to learn more about regexp...
 Any tutorials you guys can recommend?

I have to confess that after fiddling with regexps for quite a while
with no great success, I learnt the hard (and best) way, i.e. using
them to write something vile and horrible. [*] I commend this path to
you also. ;-)

Cheers,

  Peter

[*] http://git.gpleda.org/?p=gaf.git;a=blob;f=libgeda/desktop-i18n;h=6fab9b85b

-- 
Peter Brett pe...@peter-b.co.uk
Remote Sensing Research Group
Surrey Space Centre
-- 
http://mail.python.org/mailman/listinfo/python-list