How to use regex search to search a variable value

Question

I have multiple lines where i need to select only those lines which contains a specific value. For instance,

[DEBUG] 2014-12-01 16:39:12,049 [1984] Agent Logger Initialized
[DEBUG] 2014-12-01 16:39:12,049 [2884] Agent Logger Initialized
[DEBUG] 2014-12-01 16:39:12,049 [2884] Agent Actuation Logger Initialized

so i have a variable as var=1984.

id=re.search(r'\[var\],s,re.I|re.M|re.S)
if id:
   print line

THe above regex is expected to search only the var=1984 and should print lines containing that value "[1984]".Could anyone suggest how to do this?I need this to search in Linux and i am using Python 2.6.

Answer 1

this regex should work:

var=1984
reg = '.+'+str(var)+'.+'
id=re.search(reg,s,re.I|re.M|re.S)

or for simple:

import re

s = ['[DEBUG] 2014-12-01 16:39:12,049 [1984] Agent Logger Initialized',
     '[DEBUG] 2014-12-01 16:39:12,049 [2884] Agent Logger Initialized',
     '[DEBUG] 2014-12-01 16:39:12,049 [2884] Agent Actuation Logger Initialized']

var = 1984
for line in s:
    id = re.findall(r'.+%d.+' % var, line, re.I | re.M | re.S)
    if id:
        print line

output:

[DEBUG] 2014-12-01 16:39:12,049 [1984] Agent Logger Initialized

Answer 2

You can also do it with a simple if condition:

from io import StringIO

text = StringIO(u"""\
[DEBUG] 2014-12-01 16:39:12,049 [1984] Agent Logger Initialized
[DEBUG] 2014-12-01 16:39:12,049 [2884] Agent Logger Initialized
[DEBUG] 2014-12-01 16:39:12,049 [2884] Agent Actuation Logger Initialized
""")

for line in text:
    if '[1984]' in line:
        print line

[DEBUG] 2014-12-01 16:39:12,049 [1984] Agent Logger Initialized

Answer 3

This should work:

#!/usr/bin/env python
# -*- coding: utf-8 -*-

import re
var = '\[1984\]'
with open("test.log")  as fp: # assuming your log file is test.log
    lines = fp.readlines()
    for line in lines:
        line = line.strip()
        if re.match(r'.*'+str(var)+'.*',line): # may be you want to add some more strict matching rules here.
            print line

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