Question

Good morning guys

Is there a good way to use regular expression in C# in order to find all filenames and their paths within a string variable?

For example, if you have this string:

string s = @"Hello John

these are the files you have to send us today: <file>C:\Development\Projects 2010\Accounting\file20101130.csv</file>, <file>C:\Development\Projects 2010\Accounting\orders20101130.docx</file>

also we would like you to send <file>C:\Development\Projects 2010\Accounting\customersupdated.xls</file>

thank you";

The result would be:

C:\Development\Projects 2010\Accounting\file20101130.csv
C:\Development\Projects 2010\Accounting\orders20101130.docx
C:\Development\Projects 2010\Accounting\customersupdated.xls

EDITED:
Considering what told @Jim, I edited the string adding tags in order to make it easier to extract needed file names from string!

Answer 1

Here’s something I came up with:

using System;
using System.Text.RegularExpressions;

public class Test
{

    public static void Main()
    {
        string s = @"Hello John these are the files you have to send us today: 
            C:\projects\orders20101130.docx also we would like you to send 
            C:\some\file.txt, C:\someother.file and d:\some file\with spaces.ext  

            Thank you";

        Extract(s);

    }

    private static readonly Regex rx = new Regex
        (@"[a-z]:\\(?:[^\\:]+\\)*((?:[^:\\]+)\.\w+)", RegexOptions.IgnoreCase);

    static void Extract(string text)
    {
        MatchCollection matches = rx.Matches(text);

        foreach (Match match in matches)
        {
            Console.WriteLine("'{0}'", match.Value);
        }
    }

}

Produces: (see on ideone)

'C:\projects\orders20101130.docx', file: 'orders20101130.docx'
'C:\some\file.txt', file: 'file.txt'
'C:\someother.file', file: 'someother.file'
'd:\some file\with spaces.ext', file: 'with spaces.ext'

The regex is not extremely robust (it does make a few assumptions) but it worked for your examples as well.

---

Here is a version of the program if you use <file> tags. Change the regex and Extract to:

private static readonly Regex rx = new Regex
    (@"<file>(.+?)</file>", RegexOptions.IgnoreCase);

static void Extract(string text)
{
    MatchCollection matches = rx.Matches(text);

    foreach (Match match in matches)
    {
        Console.WriteLine("'{0}'", match.Groups[1]);
    }
}

Also available on ideone.