regex line by line over file topic

I can't get this to work.
It runs but there is no output when I try it on a file.


#!/usr/bin/python

import os
import sys
import re
from datetime import datetime

#logDir = '/nfs/projects/equinox/platformTools/RTLG/RTLG_logs';
#os.chdir( logDir );

programName = sys.argv[0]
fileName = sys.argv[1]

#pattern = re.compile('\s*\"SHELF-.*,SC,.*,:\"Log Collection In Progress\"')
re.M
p = re.compile('^\s*\"SHELF-.*,SC,.*,:\\"Log Collection In Progress\\"')
l = ' "SHELF-17:LOG_COLN_IP,SC,03-25,01-18-58,NEND,NA,,,:\"Log Collection In Progress\",NONE:1700000035-6364-1048,:YEAR=2014,MODE=NONE"'

# this works :-)
m = p.match( l )
if m:
print( l )

# this doesn't match anything (or the if doesn't work) :-(
with open(fileName) as f:
for line in f:
# debug code (print the line without adding a linefeed)
# sys.stdout.write( line )
if p.match(line):
print(line)


The test file just has one line:
"SHELF-17:LOG_COLN_IP,SC,03-25,01-18-58,NEND,NA,,,:\"Log Collection In Progress\",NONE:1700000035-6364-1048,:YEAR=2014,MODE=NONE"

Re: Find and replace multiple RegEx search expressions topic

Jignesh Sutar wrote:

> Hi,
>
> I'm trying to delete contents of a .txt log file, matching on multiple
> re.sub criteria but not sure how to achieve this.
>
> Below is an illustration of what I am trying to achieve (of course in this
> example I can combine the 3 re.sub into a single re expression but my
> actual code will have a dozen plus expression I need to match on so easier
> to keep them separate). Only the last re.sub will take effect in the
> example below I need all 3 to take effect.
>
>
> import re
> o = open(r"c:\temp\outputfile.txt","w")
> data = open(r"C:\Temp\infile.txt").read()
> o.write( re.sub(".*<X> ","",data) )
> o.write( re.sub(".*<Y> ","",data) )
> o.write( re.sub(".*<Z> ","",data) )
> o.close()

Apply all substitutions to data before you write the result to the file:

with open(infile) as f:
data = f.read()

for expr in list_of_regexes:
data = re.sub(expr, "", data)

with open(outfile, "w") as f:
f.write(data)

Find and replace multiple RegEx search expressions topic

Hi,

I'm trying to delete contents of a .txt log file, matching on multiple
re.sub criteria but not sure how to achieve this.

Below is an illustration of what I am trying to achieve (of course in this
example I can combine the 3 re.sub into a single re expression but my
actual code will have a dozen plus expression I need to match on so easier
to keep them separate). Only the last re.sub will take effect in the
example below I need all 3 to take effect.


import re
o = open(r"c:\temp\outputfile.txt","w")
data = open(r"C:\Temp\infile.txt").read()
o.write( re.sub(".*<X> ","",data) )
o.write( re.sub(".*<Y> ","",data) )
o.write( re.sub(".*<Z> ","",data) )
o.close()


Thanks in advance.
Jignesh

Re: Regex replacement via external command topic

Rainer Weikusat <(E-Mail Removed)> writes:

[...]


> Contrived example which can actually be executed:
>
> -----------------
> undef $/;
> my $input = <STDIN>;
>
> for ($input) {
> /\G(x+)/gc and do {
> my $fh;
>
> open($fh, '| tr x y');

This is sort-of a silly example pipe because the output would be
identical when everything was just piped through tr. A slightly less
silly example would be

open($fh, '| sed "s/./y/g"');

This uses sed to replace every input byte with an y. As can easily be
verified, it only runs for x in the input, not for any other character.