Where to put regex conditions on streamwriting C#

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I want to add new regex to my code, which prints from list (with streamreader).
Where to add regex which removes these characters( - : _ |) from file and regex to add header to the file.

regex of replacing char: line.Replace(@"- : _ |", string.Empty);

regex for adding header:

C#

using (StreamWriter file = new StreamWriter(fs))                    
{
    file.WriteLine( "Number,User,Function,Message"); 

    for (int index = 0; index < pr.Length; index++)
    {
      
        file.WriteLine("{0},\"{1}\",{2},{3}",
           pr[s].Number, pr[s].User,
           pr[s].Function, pr[s].Message; 
    }
}

What I have tried:

C#

using (StreamWriter writer = new StreamWriter(path2))
            {
                foreach (string l in inactive)
                {

           //line.Replace(@"- : _ |", string.Empty); 
                    writer.WriteLine(l);
}
}

Posted 17-Nov-17 1:30am

anabeth4

Updated 17-Nov-17 1:58am

Andy Lanng

v2

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Comments

Richard MacCutchan 17-Nov-17 7:41am

What is wrong with using the string.Replace method?

anabeth4 17-Nov-17 7:46am

i tried but it doesn't remove the characters

3 solutions

Solution 1

Quote:
i want to remove not replace those characters

That's what replacing them with an empty string does - it removes the characters.
If you want to remove all those characters regardless of where rgey appear, ratehr than as a single string, you have teh wrong regex.
Your regex will change this

Hello -:_|There!

To this:

Hello There!

But will leave this unchanged:

Hello -:There!_|

If you want to remove all instances of any of the characters, you need this regex:

[-:_|]+

Get a copy of Expresso[^] - it's free, and it examines and generates Regular expressions.

But that code is looking very much like the code used by a member who is starting to become rather a Help Vampire / Troll because he refuses to learn anything and think for himself ... I smell a sock puppet here...

Posted 17-Nov-17 1:51am

OriginalGriff

Comments

anabeth4 17-Nov-17 8:32am

maybe different people same hw? this page supposed to help others not to make irony ;)
thnx!

Solution 2

You should try to replace

@"- : _ |"

with

@"[- : _ |]"

Just a few interesting links to help building and debugging RegEx.
Here is a link to RegEx documentation:
perlre - perldoc.perl.org[^]
Here is links to tools to help build RegEx and debug them:
.NET Regex Tester - Regex Storm[^]
Expresso Regular Expression Tool[^]
RegExr: Learn, Build, & Test RegEx[^]
This one show you the RegEx as a nice graph which is really helpful to understand what is doing a RegEx:
Debuggex: Online visual regex tester. JavaScript, Python, and PCRE.[^]

Posted 17-Nov-17 1:51am

Patrice T

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phil.o · Accepted Answer · 2017-11-17T01:58:00

You cannot use string.Replace this way (using a global string); you have to use a string.Replace for each character to replace.
Example:

C#

l = l.Replace("-", "").Replace(":", "").Replace("_", "").Replace("|", "");

Notes:
- string.Replace does not proceed to an in-place editing of the variable, you have to cast the result of the method to the variable again (l = ...).
- You can chain the calls to the Replace method.
- In the code block you showed, in the commented line, you seem to use a line which does not match the l variable defined in your foreach loop.
There are other options to do the same, using regular expressions for example, but I think some directions already have been given to you on this subject in some other posts.
Hope this helps. Kindly.