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start from end of string till special character c#

This is probably a super easy question but I can't seem to figure it out. Do you know how to extract just the portion after the '/' in a string. So for like the following:
[HKEY_LOCAL_MACHINE\SOFTWARE\4YourSoul\Server\ReportEMailService\OrderConfirmation_SynergyWorldInc]
So I just want the 'OrderConfirmation_SynergyWorldInc' portion. I got 271 entries where I gotta extract just the end portion (the all have the portions before that in all of them, if that helps).
Thanks!!

IF YOU HAVE A SINGLE ENTRY...
You need to use LastIndexOf with Substring after a bit of trimming:
var s = #"[HKEY_LOCAL_MACHINE\SOFTWARE\4YourSoul\Server\ReportEMailService\OrderConfirmation_SynergyWorldInc]";
s = s.Trim('[',']');
Console.Write(s.Substring(s.LastIndexOf('\\') + 1));
Result: OrderConfirmation_SynergyWorldInc
IF YOU HAVE MULTIPLE RECORDS...
You can use a regex to extract multiple matches from a large text containing [...] substring:
[^\\\[\]]+(?=\])
See demo
For [HKEY_LOCAL_MACHINE\SOFTWARE\4YourSoul\Server\ReportEMailService\OrderConfirmation_SynergyWorldInc][SOMEENTRY] string, you will then get 2 results:
The regex matches
[^\\\[\]]+ - 1 or more characters other than ], [ and \
(?=\]) - before the end ] character.
C#:
var results = Regex.Matches(s, #"[^\\\[\]]+(?=\])").OfType<Match>().Select(p => p.Value).ToList();

var s = #"[HKEY_LOCAL_MACHINE\SOFTWARE\4YourSoul\Server\ReportEMailService\OrderConfirmation_SynergyWorldInc]";
Console.WriteLine (s.Trim(']').Split('\\').Last());
prints
OrderConfirmation_SynergyWorldInc

var key = #"[HKEY_LOCAL_MACHINE\SOFTWARE\4YourSoul\Server\ReportEMailService\OrderConfirmation_SynergyWorldInc]";
key = key.Replace("[", string.Empty);
key = key.Replace("]", string.Empty);
var splitkeys =key.Split('\\');
if (splitkeys.Any())
{
string result = splitkeys.Last();
}

Try:
string orderConfirmation = yourString.Split(new []{'\\\'}).Last();
You may also want to remove the last character if the brackets are included in the string.

string pattern = ".*\\(\w*)";
string value = "[HKEY_LOCAL_MACHINE\SOFTWARE\4YourSoul\Server\ReportEMailService\OrderConfirmation_SynergyWorldInc]"
Regex r = new Regex(pattern);
Match m = r.Match(value);

Regex to extract data from card swipe

I'm searching for a regular expression that will extract 0263563
from
;010263563=2119?
and 0267829
from
%00000026782904?;010267829=4119?
(Must be the same regular expression).

Start at the 3rd character after the semicolon and take 7 characters.
;..(\d{7})
or more general:
;..(.{7})
Or according to comment : "To clarify characters to take are digits"
;\d\d(\d{7})

Well, you need this:
;\d{2}(\d+)
The First group will contain the number you want.

;[\S]{2}([\S]{7})
Since you said characters and not numbers, but it would work either way

For rules that are that precise (start 3 chars after ;, then next 7), you could use a plain substring:
string s = "%00000026782904?;010267829=4119?";
var pos = s.IndexOf(';');
var number = s.Substring(pos+3, 7);
And of course, test whether that IndexOf really found the ;

The below regex would exactly 7 digits which must be preceded by a ; , any two characters.
(?<=;.{2})\d{7}
Code:
String input = #";010263563=2119?
%00000026782904?;010267829=4119?";
Regex rgx = new Regex(#"(?<=;.{2})\d{7}");
foreach (Match m in rgx.Matches(input))
Console.WriteLine(m.Groups[0].Value);
IDEONE
Output:
0263563
0267829

Assuming regex is not an absolute requirement, you could use:
var input = "%00000026782904?;010267829=4119?";
// output will be: 0267829
var digits = input.SkipWhile(x => x != ';').Skip(3).Take(7).ToArray();
var output = new string(digits);

Regex cut number in a string c#

I have a string as following 2 - 5 now I want to get the number 5 with Regex C# (I'm new to Regex), could you suggest me an idea? Thanks

You can use String.Split method simply:
int number = int.Parse("2 - 5".Split('-', ' ').Last());
This will work if there is no space after the last number.If that is the case then:
int number = int.Parse("2 - 5 ".Split('-', ' ')
.Last(x => x.Any() && x.All(char.IsDigit)));

Very simply as follows:
'\s-\s(\d)'
and extract first matching group

#SShashank has the right of it, but I thought I'd supply some code, since you mentioned you were new to Regex:
string s = "something 2-5 another";
Regex rx = new Regex(#"-(\d)");
if (rx.IsMatch(s))
{
Match m = rx.Match(s);
System.Console.WriteLine("First match: " + m.Groups[1].Value);
}
Groups[0] is the entire match and Groups[1] is the first matched group (stuff in parens).

If you really want to use regex, you can simply do:
string text = "2 - 5";
string found = Regex.Match(text, #"\d+", RegexOptions.RightToLeft).Value;

C# Regex match all occurrences

I'm trying to make a Regular Expression in C# that will match strings like"
", but my Regex stops at the first match, and I'd like to match the whole string.
I've been trying with a lot of ways to do this, currently, my code looks like this:
string sPattern = #"/&#\d{2};/";
Regex rExp = new Regex(sPattern);
MatchCollection mcMatches = rExp.Matches(txtInput.Text);
foreach (Match m in mcMatches) {
if (!m.Success) {
//Give Warning
}
}
And also tried lblDebug.Text = Regex.IsMatch(txtInput.Text, "(&#[0-9]{2};)+").ToString(); but it also only finds the first match.
Any tips?
Edit:
The end result I'm seeking is that strings like &# are labeled as incorrect, as it is now, since only the first match is made, my code marks this as a correct string.
Second Edit:
I changed my code to this
string sPattern = #"&#\d{2};";
Regex rExp = new Regex(sPattern);
MatchCollection mcMatches = rExp.Matches(txtInput.Text);
int iMatchCount = 0;
foreach (Match m in mcMatches) {
if (m.Success) {
iMatchCount++;
}
}
int iTotalStrings = txtInput.Text.Length / 5;
int iVerify = txtInput.Text.Length % 5;
if (iTotalStrings == iMatchCount && iVerify == 0) {
lblDebug.Text = "True";
} else {
lblDebug.Text = "False";
}
And this works the way I expected, but I still think this can be achieved in a better way.
Third Edit:
As #devundef suggest, the expression "^(&#\d{2};)+$" does the work I was hopping, so with this, my final code looks like this:
string sPattern = #"^(&#\d{2};)+$";
Regex rExp = new Regex(sPattern);
lblDebug.Text = rExp.IsMatch(txtInput.Text).ToString();
I always neglect the start and end of string characters (^ / $).

Remove the / at the start and end of the expression.
string sPattern = #"&#\d{2};";
EDIT
I tested the pattern and it works as expected. Not sure what you want.
Two options:
&#\d{2}; => will give N matches in the string. On the string 
 it will match 2 groups,  and 

(&#\d{2};)+ => will macth the whole string as one single group. On the string 
 it will match 1 group, 

Edit 2:
What you want is not get the groups but know if the string is in the right format. This is the pattern:
Regex rExp = new Regex(#"^(&#\d{2};)+$");
var isValid = rExp.IsMatch("
") // isValid = true
var isValid = rExp.IsMatch("xyz
") // isValid = false

Here you go: (&#\d{2};)+ This should work for one occurence or more

(&#\d{2};)*
Recommend: http://www.weitz.de/regex-coach/

C# - Regular Expression for NO numbers allowed

I want to validate first name and last name from all existing languages.
So I want to validate that there are numbers in a string.
Thanks

[\s\p{L}]
would be the correct character class for this. But of course names can contain many more characters than those (how about Tim O'Reilly or William Henry Gates III.?).
See also Falsehoods Programmers Believe About Names.

Don't even have to use regex:
string tmp = "foo";
var match = tmp.IndexOfAny("0123456789".ToCharArray()) != -1;

Just do !Regex if your validation is in a if statement.
if ( !Regex.Match ( stringToCheck, "^[0-9]+$" ).Success ) {
// TODO.
}

I just tried this one and it should do the trick:
var regex = new Regex(#"[0-9]", RegexOptions.IgnoreCase);
var m = regex.Match(stringValue);
if (m.Success)
//TODO