Conversion of perl based regex to python method
andrew.arobert at gmail.com
Wed May 24 20:24:55 CEST 2006
Andrew Robert wrote:
> I have two Perl expressions
> If windows:
> perl -ple "s/([^\w\s])/sprintf(q#%%%2X#, ord $1)/ge" somefile.txt
> If posix
> perl -ple 's/([^\w\s])/sprintf("%%%2X", ord $1)/ge' somefile.txt
> The [^\w\s] is a negated expression stating that any character
> a-zA-Z0-9_, space or tab is ignored.
> The () captures whatever matches and throws it into the $1 for
> processing by the sprintf
> In this case, %%%2X which is a three character hex value.
> How would you convert this to a python equivalent using the re or
> similar module?
> I've begun reading about using re expressions at
> http://www.amk.ca/python/howto/regex/ but I am still hazy on implementation.
> Any help you can provide would be greatly appreciated.
Okay.. I got part of it..
The code/results below seem to do the first part of the expression.
I believe the next part is iterating across each of the characters,
evaluate the results and replace with hex as needed.
# Import the module
# Open test file
# Read in a sample line
# Compile expression to exclude all characters plus space/tab
# Look to see if I can find a non-standard character
# from test line #! C:\Python24\Python
<_sre.SRE_Match object at 0x009DA8E0
# I got
# See if pattern will come back with something it shouldn't
Instead of being so linear, I was thinking that this might be closer.
Got to figure out the hex line but then we are golden
# Evaluate captured character as hex
return chr((ord(ch) + 1) % )
# Evaluate the value of whatever was matched
# open file
file = open(r'm:\mq\mq\scripts\testme.txt','r')
# Read each line, pass any matches on line to function
for line in file.readlines():
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