* @ Rocteur CC:
On 27 Feb 2010, at 12:44, Steven D'Aprano wrote:
On Sat, 27 Feb 2010 10:36:41 +0100, @ Rocteur CC wrote:
cat file.dos | python -c "import sys,re;
[sys.stdout.write(re.compile('\r\n').sub('\n', line)) for line in
sys.stdin]" >file.unix
Holy cow!!!!!!! Calling a regex just for a straight literal-to-literal
string replacement! You've been infected by too much Perl coding!
Thanks for the replies I'm looking at them now, however, for those who
misunderstood, the above cat file.dos pipe pythong does not come from
Perl but comes from:
http://wiki.python.org/moin/Powerful%20Python%20One-Liners
Steven is right with the "Holy Cow" and multiple exclamation marks.
For those unfamiliar with that, just google "multiple exclamation marks", I
think that should work... ;-)
Not only is a regular expression overkill & inefficient, but the snippet also
needlessly constructs an array with size the number of lines.
Consider instead e.g.
<hack>
import sys; sum(int(bool(sys.stdout.write(line.replace('\r\n','\n')))) for line
in sys.stdin)
</hack>
But better, consider that it's less work to save the code in a file than copying
and pasting it in a command interpreter, and then it doesn't need to be 1 line.
Apply regular expression to lines from stdin
[another command] | python -c "import
sys,re;[sys.stdout.write(re.compile('PATTERN').sub('SUBSTITUTION',
line)) for line in sys.stdin]"
Nothing to do with Perl, Perl only takes a handful of characters to do
this and certainly does not require the creation an intermediate file, I
simply found the above example on wiki.python.org whilst searching
Google for a quick conversion solution.
Thanks again for the replies I've learned a few things and I appreciate
your help.
Cheers,
- Alf
--
http://mail.python.org/mailman/listinfo/python-list
