Using Regex to omit and replace special charecters

Rano AH

Hi Sunny kumar

using Regex, I need to do the following:

Replacing * with X when found

omit / when found in

- _ are allowed

Upper case and Lower case are allowed

Numerical format and alphanumeric format are allowed

Do I need also to use RegexOptions.None instead of the following? I still cannot understand Regex very well :-( but I keep trying

Regex regex = new Regex("(?:[^]|(?<=['\"])s)", RegexOptions.IgnoreCase | RegexOptions.CultureInvariant | RegexOptions.Compiled);

4 Replies

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

Vulpes13y ago
Accepted answer
As Sunny doesn't seem to be here just now, I thought I'd answer :)

You have essentially three separate operations here - two replacements and a match of the resulting string. The following code should achieve that:

using System;
using System.Text.RegularExpressions;

class Test
{
static void Main()
{
string text = @"12/abCD*_34-5/6*";
text = Regex.Replace(text, @"\*", "X");
Console.WriteLine(text); // 12/abCDX_34-5/6X
text = Regex.Replace(text, @"/", "");
Console.WriteLine(text); // 12abCDX_34-56X
bool b = Regex.IsMatch(text, @"^[a-z0-9_-]+$", RegexOptions.IgnoreCase);
Console.WriteLine(b); // True
Console.ReadKey();
}
}

RegexOptions.None means apply no options and so can only be used on its own.

However, you shouldn't need to use it much as most Regex methods will have overloads which don't require a RegexOptions parameter in any case.
0
Rano AH13y ago
Hi

I must be mistaken on this. My codes works perfectly :-), I just forgot that list index begins with [0] instead of [1]. So If I need to read line four, I just need to pass list[3] instead of list[4]. What a mistake :-)

Anyway, thanks for the help Vulpes, I found you guys on time all the time :-)
If I encounter some problems, for sure I will get back to you guys for the assistance :-)
0
Vulpes13y ago
Well, at the moment it doesn't appear to be skipping anything - it's just reading the first 10 lines.

So, are you saying that you want it it to skip any line which begins with 0 or some other number or which otherwise contains alphanumeric characters?

If so, it would help if you could post a sample file so I can see exactly what needs to be skipped here.
0
Rano AH13y ago
ear Vulpes
Thank you for replying my question. Any one of you guys is welcome to answer my questions. :-)
See my code below please:

if (Files.Lenght > 0)
foreach (string file in files)
{
try
{
var list = new List();
using (var reader = new StreamReader(file))
                        {
                            for (int i = 0; i < 10; i++)
                            {
                                list.Add(reader.ReadLine());
                            }
                        }
string newFileName = string.Concat(Path.GetFileNameWithoutExtension(file), "-",list[3], "-", list[8],"-",list[9],"-",list[10], "txt");
newFileName=Regex.Replace(newFileName, @"\*", "X");
newFileName = Regex.Replace(newFileName, @"\/", "");
string newFile = string.Concat(outputDirectory,"\\",newFileName,".txt");
File.Copy(file, newFile);
This code works fine, but still I face some problems in which I'm trying to solve:
When I read the file, it skips the rows which begins with 0, or number or if it contains alphanumeric characters. in this case it reads line 4 instead of three for instance and line 9 instead of 8 and so on.. This will give me incorrect file name
0