How to Implement Regular expression to a Text File

sampath meka

Hello All,

I have one query regarding regular expression implementation to a file.I have a large text file in which i am providing a set of lines has example:

/SCS/SCS_Core_Based/08_Software/Application/YIB/YIB_GEN2/MAIN/APPLICATION/DOCS/Private/TestSpecifications/yib_polyspace_drs.h 1.3 d:\Sandbox\BMW35UP_I390_1.443_Testview\MainMicro\Application\Yib\Yib_Main\_yib_lat_accel_signals\yib_polyspace_drs.h
/SCS/SCS_Core_Based/08_Software/Application/YIB/YIB_GEN2/MAIN/APPLICATION/SOURCE/yib_swa_signals.h 1.10.1.4 d:\Sandbox\BMW35UP_I390_1.443_Testview\MainMicro\Application\Yib\Yib_Main\_yib_lat_accel_signals\yib_swa_signals.h
/SCS/SCS_Core_Based/08_Software/Application/YIB/YIB_GEN2/MAIN/APPLICATION/SOURCE/yib_swa_signals_sub.h 1.11.1.4 d:\Sandbox\BMW35UP_I390_1.443_Testview\MainMicro\Application\Yib\Yib_Main\_yib_lat_accel_signals\yib_swa_signals_sub.h
/SCS/SCS_Core_Based/08_Software/Application/YIB/YIB_GEN2/MAIN/APPLICATION/DOCS/Private/TestSpecifications/yib_polyspace_drs.h 1.3 d:\Sandbox\BMW35UP_I390_1.443_Testview\MainMicro\Application\Yib\Yib_Main\_yib\yib_polyspace_drs.h
/SCS/SCS_Core_Based/08_Software/Application/YIB/YIB_GEN2/MAIN/APPLICATION/SOURCE/yib_swa_signals_trim.h 1.4.1.5 d:\Sandbox\BMW35UP_I390_1.443_Testview\MainMicro\Application\Yib\Yib_Main\_yib_lat_accel_signals\yib_swa_signals_trim.h
/SCS/SCS_Core_Based/08_Software/Application/YIB/YIB_GEN2/MAIN/APPLICATION/DOCS/Private/TestSpecifications/yib_polyspace_drs.h 1.3 d:\Sandbox\BMW35UP_I390_1.443_Testview\MainMicro\Application\Yib\Yib_Main\_yib_fault_manager\yib_polyspace_drs.h
/SCS/SCS_Core_Based/08_Software/Application/YIB/YIB_GEN2/MAIN/APPLICATION/DOCS/Private/TestSpecifications/yib_polyspace_drs.h 1.3 d:\Sandbox\BMW35UP_I390_1.443_Testview\MainMicro\Application\Yib\Yib_Main\_yib_fwd_rev_detection\yib_polyspace_drs.h
/SCS/SCS_Core_Based/08_Software/Application/YIB/YIB_GEN2/MAIN/APPLICATION/SOURCE/yib_swa_signals_priv.h 1.9 d:\Sandbox\BMW35UP_I390_1.443_Testview\MainMicro\Application\Yib\Yib_Main\_yib_lat_accel_signals\yib_swa_signals_priv.h
/SCS/SCS_Core_Based/08_Software/Application/YIB/YIB_GEN2/MAIN/APPLICATION/DOCS/Private/TestSpecifications/yib_polyspace_drs.h 1.3 d:\Sandbox\BMW35UP_I390_1.443_Testview\MainMicro\Application\Yib\Yib_Main\_yib_initialization\yib_polyspace_drs.h

if i give filename has yib_polyspace_drs.h then i should get below lines has output from regular expression

Kindly help me to implement regular expression .

Thanks & Regards,

Sampath

3 Replies

Know the answer? Post it — somebody with the same question will find it here.

Vulpes12y ago
Accepted answer
OK, if that's what you want, try this:

using System;
using System.IO;
using System.Text.RegularExpressions;

class Program
{
static void Main()
{
string text = File.ReadAllText("sampath_meka.txt");
string reg = @"(?m)^.*?yib_polyspace_drs\.h.*$";
MatchCollection mc = Regex.Matches(text, reg);
foreach(Match m in mc) Console.WriteLine(m.Value);
Console.ReadKey();
}
}

The output is:

/SCS/SCS_Core_Based/08_Software/Application/YIB/YIB_GEN2/MAIN/APPLICATION/DOCS/P
rivate/TestSpecifications/yib_polyspace_drs.h 1.3 d:\Sandbox\BMW35UP_I390_1.443_
Testview\MainMicro\Application\Yib\Yib_Main\_yib_lat_accel_signals\yib_polyspace
_drs.h
/SCS/SCS_Core_Based/08_Software/Application/YIB/YIB_GEN2/MAIN/APPLICATION/DOCS/P
rivate/TestSpecifications/yib_polyspace_drs.h 1.3 d:\Sandbox\BMW35UP_I390_1.443_
Testview\MainMicro\Application\Yib\Yib_Main\_yib\yib_polyspace_drs.h
/SCS/SCS_Core_Based/08_Software/Application/YIB/YIB_GEN2/MAIN/APPLICATION/DOCS/P
rivate/TestSpecifications/yib_polyspace_drs.h 1.3 d:\Sandbox\BMW35UP_I390_1.443_
Testview\MainMicro\Application\Yib\Yib_Main\_yib_fault_manager\yib_polyspace_drs
.h
/SCS/SCS_Core_Based/08_Software/Application/YIB/YIB_GEN2/MAIN/APPLICATION/DOCS/P
rivate/TestSpecifications/yib_polyspace_drs.h 1.3 d:\Sandbox\BMW35UP_I390_1.443_
Testview\MainMicro\Application\Yib\Yib_Main\_yib_fwd_rev_detection\yib_polyspace
_drs.h
/SCS/SCS_Core_Based/08_Software/Application/YIB/YIB_GEN2/MAIN/APPLICATION/DOCS/P
rivate/TestSpecifications/yib_polyspace_drs.h 1.3 d:\Sandbox\BMW35UP_I390_1.443_
Testview\MainMicro\Application\Yib\Yib_Main\_yib_initialization\yib_polyspace_dr
s.h
sampath meka12y ago
Mine is a large file i want to implement regex for the file buffer which should result the matches in the buffer.Kindly help me in this regard
Vulpes12y ago
Well, if it's a large text file, I'd avoid loading all of it into memory at the same time.

Instead, I'd read it line by line using a StreamReader, check whether each line contains the string you're looking for and, if it does, add it to a list of results.

You don't need regular expressions for this but can use the String.IndexOf method to check for the presence of the string within each line.