We Keep Coding

RegEx string between N and (N+1)th Occurance

I am attempting to find nth occurrence of sub string between two special characters. For example.
one|two|three|four|five
Say, I am looking to find string between (n and n+1 th) 2nd and 3rd Occurrence of '|' character, which turns out to be 'three'.I want to do it using RegEx. Could someone guide me ?
My Current Attempt is as follows.
string subtext = "zero|one|two|three|four";
Regex r = new Regex(#"(?:([^|]*)|){3}");
var m = r.Match(subtext).Value;

If you have full access to C# code, you should consider a mere splitting approach:
var idx = 2; // Might be user-defined
var subtext = "zero|one|two|three|four";
var result = subtext.Split('|').ElementAtOrDefault(idx);
Console.WriteLine(result);
// => two
A regex can be used if you have no access to code (if you use some tool that is powered with .NET regex):
^(?:[^|]*\|){2}([^|]*)
See the regex demo. It matches
^ - start of string
(?:[^|]*\|){2} - 2 (or adjust it as you need) or more sequences of:
[^|]* - zero or more chars other than |
\| - a | symbol
([^|]*) - Group 1 (access via .Groups[1]): zero or more chars other than |
C# code to test:
var pat = $#"^(?:[^|]*\|){{{idx}}}([^|]*)";
var m = Regex.Match(subtext, pat);
if (m.Success) {
Console.WriteLine(m.Groups[1].Value);
}
// => two
See the C# demo
If a tool does not let you access captured groups, turn the initial part into a non-consuming lookbehind pattern:
(?<=^(?:[^|]*\|){2})[^|]*
^^^^^^^^^^^^^^^^^^^^
See this regex demo. The (?<=...) positive lookbehind only checks for a pattern presence immediately to the left of the current location, and if the pattern is not matched, the match will fail.

Use this:
(?:.*?\|){n}(.[^|]*)
where n is the number of times you need to skip your special character. The first capturing group will contain the result.
Demo for n = 2

Use this regex and then select the n-th match (in this case 2) from the Matches collection:
string subtext = "zero|one|two|three|four";
Regex r = new Regex("(?<=\|)[^\|]*");
var m = r.Matches(subtext)[2];

How to get two numerical values from a string in C#

I have a string like this :
X LIMITED COMPANY (52100000/58447000)
I want to extract X LIMITED COMPANY, 52100000 and 58447000 seperately.
I'm extracting X LIMITED COMPANY like this :
companyName = Regex.Match(mystring4, #"[a-zA-Z\s]+").Value.Trim();
But I'm stuck with extracting numbers, they can be 1, 2 or large numbers in the example. Can you show me how to extract those numbers? Thanks.

Try regular expressions with alternative | (or):
Either word symbols (but not digits) [\w-[\d]][\w\s-[\d]]+)
Digits only ([0-9]+)
E.g.
string mystring4 = #"AKASYA CAM SANAYİ VE TİCARET LİMİTED ŞİRKETİ(52100000 / 58447000)";
string[] values = Regex
.Matches(mystring4, #"([\w-[\d]][\w\s-[\d]]+)|([0-9]+)")
.OfType<Match>()
.Select(match => match.Value.Trim())
.ToArray();
Test
// X LIMITED COMPANY
// 52100000
// 58447000
Console.Write(string.Join(Environment.NewLine, values));
I suggested changing the initial pattern [a-zA-Z\s]+ into [a-zA-Z][a-zA-Z\s]+ in order to skip matches which contain separators only (e.g. " ")

Try using named groups:
var s = "X LIMITED COMPANY (52100000 / 58447000)";
var regex = new Regex(#"(?<CompanyName>[^\(]+)\((?<Num1>\d+)\s*/\s*(?<Num2>\d+)\)");
var match = regex.Match(s);
var companyName = match.Groups["CompanyName"];

If the format is fixed, you could try this:
var regex = new Regex(#"^(?<name>[^\(]+)\((?<n1>\d+)/(?<n2>\d+)\)");
var match = regex.Match(input);
var companyName = match.Groups["name"].Value;
var number1 = Convert.ToInt64(match.Groups["n1"].Value);
var number2 = Convert.ToInt64(match.Groups["n2"].Value);
This matches everything up to the open parentheses and puts it into a named group "name". Then it matches two numbers within parentheses, separated by "/" and puts them into groups named "n1" and "n2" respectively.

Replace matches AFTER having processed the match

In my program I am implementing tokens to be replaced with variable values.
Such a token is #INT[1-5] (meaning it will get replaced with a random int between 1 and 5.
I have already written the regex to match the token: #INT[\d+-\d+]
However I don't know how to replace the token (after having processed the match and calculated the random number.
So far I have the following:
Random random = new Random();
Regex regex = new Regex(#"#INT\[\d+-\d+\]");
MatchCollection matches = regex.Matches("This is one of #INT[1-5] tests");
foreach (Match m in matches)
{
if (m.Success)
{
var ints = m.Value.Split('-').Select(x => Convert.ToInt32(x)).ToArray();
int intToInsert = random.Next(ints[0], ints[1]);
//now how do I insert the int in place of the match?
}
}

I think you need to make use of the match evaluator with Regex.Replace and use capturing groups around the numbers in your regex:
var regex = new Regex(#"#INT\[(\d+)-(\d+)\]");
// ^ ^ ^ ^
var res = regex.Replace("This is one of #INT[1-5] tests", m =>
random.Next(Convert.ToInt32(m.Groups[1].Value), Convert.ToInt32(m.Groups[2].Value)).ToString());
Results: This is one of 2 tests, This is one of 3 tests, ...
The captured texts can be accessed with m.Groups[n].Value.

Regexp find position of different characters in string

I have a string conforming to the following pattern:
(cc)-(nr).(nr)M(nr)(cc)whitespace(nr)
where cc is artbitrary number of letter characters, nr is arbitrary number of numerical characters, and M is is the actual letter M.
For example:
ASF-1.15M437979CA 100000
EU-12.15M121515PO 1145
I need to find the positions of -, . and M whithin the string. The problem is, the leading characters and the ending characters can contain the letter M as well, but I need only the one in the middle.
As an alternative, the subtraction of the first characters (until -) and the first two numbers (as in (nr).(nr)M...) would be enough.

If you need a regex-based solution, you just need to use 3 capturing groups around the required patterns, and then access the Groups[n].Index property:
var rxt = new Regex(#"\p{L}*(-)\d+(\.)\d+(M)\d+\p{L}*\s*\d+");
// Collect matches
var matches = rxt.Matches(#"ASF-1.15M437979CA 100000 or EU-12.15M121515PO 1145");
// Now, we can get the indices
var posOfHyphen = matches.Cast<Match>().Select(p => p.Groups[1].Index);
var posOfDot = matches.Cast<Match>().Select(p => p.Groups[2].Index);
var posOfM = matches.Cast<Match>().Select(p => p.Groups[3].Index);
Output:
posOfHyphen => [3, 32]
posOfDot => [5, 35]
posOfM => [8, 38]

Regex:
string pattern = #"[A-Z]+(-)\d+(\.)\d+(M)\d+[A-Z]+";
string value = "ASF-1.15M437979CA 100000 or EU-12.15M121515PO 1145";
var match = Regex.Match(value, pattern);
if (match.Success)
{
int sep1 = match.Groups[1].Index;
int sep2 = match.Groups[2].Index;
int sep3 = match.Groups[3].Index;
}

regex to strip number from var in string

I have a long string and I have a var inside it
var abc = '123456'
Now I wish to get the 123456 from it.
I have tried a regex but its not working properly
Regex regex = new Regex("(?<abc>+)=(?<var>+)");
Match m = regex.Match(body);
if (m.Success)
{
string key = m.Groups["var"].Value;
}
How can I get the number from the var abc?
Thanks for your help and time

var body = #" fsd fsda f var abc = '123456' fsda fasd f";
Regex regex = new Regex(#"var (?<name>\w*) = '(?<number>\d*)'");
Match m = regex.Match(body);
Console.WriteLine("name: " + m.Groups["name"]);
Console.WriteLine("number: " + m.Groups["number"]);
prints:
name: abc
number: 123456

Your regex is not correct:
(?<abc>+)=(?<var>+)
The + are quantifiers meaning that the previous characters are repeated at least once (and there are no characters since (?< ... > ... ) is named capture group and is not considered as a character per se.
You perhaps meant:
(?<abc>.+)=(?<var>.+)
And a better regex might be:
(?<abc>[^=]+)=\s*'(?<var>[^']+)'
[^=]+ will match any character except an equal sign.
\s* means any number of space characters (will also match tabs, newlines and form feeds though)
[^']+ will match any character except a single quote.
To specifically match the variable abc, you then put it like this:
(?<abc>abc)\s*=\s*'(?<var>[^']+)'
(I added some more allowances for spaces)

From the example you provided the number can be gotten such as
Console.WriteLine (
Regex.Match("var abc = '123456'", #"(?<var>\d+)").Groups["var"].Value); // 123456
\d+ means 1 or more numbers (digits).
But I surmise your data doesn't look like your example.

Try this:
var body = #"my word 1, my word 2, my word var abc = '123456' 3, my word x";
Regex regex = new Regex(#"(?<=var \w+ = ')\d+");
Match m = regex.Match(body);