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Can't make regex pattern for 8 and 13 digits in middle of string work

EDIT 2:
Yes like I thought, i need to change the pattern to 2 different ones, because the OR will make a match for 13 digits a match for 8 digits one
THE SOLUTION IS:
Regex EAN8 = new Regex(#"\b\d{8}\b");
Regex EAN13 = new Regex(#"\d{13}\b");
PS FOR EDIT2: As someone said, problaly in the future i will end up finding EAN1234567890123 or EAN_1234567890123, these patterns wont work out, and I have no idea where to start searching for a pattern like this.
I'm doing a project where I need to take multiple EANs from a text.
I already have a validation class to see if they are valid or not.
And I can take the 13 digits one (but I think the pattern I'm using is not correct and will give problems sooner or later.
Example of a string: "OL‐120 112 82 Estuchado, fácil apertura. 8410032002279 227 24"
as you can see there is a valid EAN13 in the middle: "8410032002279"
I'm using this pattern:
Regex EAN13 = new Regex(#"\d{13}");
It gives me the EAN inside the string, but I think the correct pattern should be like this:
Regex EAN13 = new Regex(#"\d{13}$");
But when I use it it doesn't work. probably because the string doesn't end there.
I have a similar problem with the EAN of 8 digits, if i use this pattern:
Regex EAN8 = new Regex(#"\d{8}");
It gives me the 13 digit eans cut to 8...
What should I do to make both patterns work whatever the position of the EAN is in the string and for the 8 digit return only a real string with 8 digits and not one with more cut down to 8.
Thanks in advance
EDIT: Further Code to understand what I'm doing
Regex EAN = new Regex(#"\b(?:\d{8}|\d{13})\b");
using (StreamReader sr = new StreamReader(#"....txt"))
{
string currentLine;
while ((currentLine = sr.ReadLine()) != null)
{
Match m13 = EAN.Match(currentLine);
Match m8 = EAN.Match(currentLine);
if (m8.Success)
{
lista_EAN8.Add(m8.Value);
//string valido8 = new Ean8Validate().ValidateEan8(m8.Value);
//if (valido8 == m8.Value)
//{
// lista_EAN8.Add(m8.Value);
//}
}
if (m13.Success)
{
string valido13 = new Ean13Validate().ValidateEan13(m13.Value);
if (valido13 == m13.Value)
{
lista_EAN13.Add(m13.Value);
}
}
}
}
Like this it returns me the same values in list of 13 digit eans and list of 8 digits eans

ok looks like you want 2 different Regexs one for targeting only 8 digit matches and the other for targeting 13 digit matches
for matching of the 8 digit EANs use;
\b(?:\d{8})\b
for matching and for 13 digit EANs use;
\b(?:\d{13})\b
additionally is you want an options prefix of EAN(upper or lowercase) you can use;
for 8 digit
\b(?:[Ee][Aa][Nn])?(?:\d{8})\b
for 13 digit
\b(?:[Ee][Aa][Nn])?(?:\d{8})\b
for your example you want to modify the code so it read something like this.
Regex EAN8 = new Regex(#"\b(?:\d{8})\b");
Regex EAN13 = new Regex(#"\b(?:\d{13})\b");
using (StreamReader sr = new StreamReader(#"....txt"))
{
string currentLine;
while ((currentLine = sr.ReadLine()) != null)
{
Match m13 = EAN13.Match(currentLine);
Match m8 = EAN8.Match(currentLine);
if (m8.Success)
{
lista_EAN8.Add(m8.Value);
}
if (m13.Success)
{
lista_EAN13.Add(m13.Value);
}
}
}
now if we tweek the Regexs a little more we can extract just the number parts out of EAN numbers even when they are prefixed with EAN* or EAN_*
Regex EAN8 = new Regex(#"\b(?:[Ee][Aa][Nn]_?)?(\d{8})\b");
Regex EAN13 = new Regex(#"\b(?:[Ee][Aa][Nn]_?)?(\d{13})\b");
using (StreamReader sr = new StreamReader(#"....txt"))
{
string currentLine;
while ((currentLine = sr.ReadLine()) != null)
{
Match m13 = EAN13.Match(currentLine);
Match m8 = EAN8.Match(currentLine);
if (m8.Success)
{
lista_EAN8.Add(m8.Groups[1].Value);
}
if (m13.Success)
{
lista_EAN13.Add(m13.Groups[1].Value);
}
}
}
this will capture the number part while throwing away the EAN prefix

Use the below regex to match 8 or 13 digits. \b is a word boundary which matches between a word character and a non-word character. So it avoids matching 8 digit number in a 13 digit number.
\b(?:\d{8}|\d{13})\b

Try this regex string. \b = word boundary and the | makes sure that it will only match 8 or 13 and not some number in between:
\b\d{8}\b|\b\d{13}\b

If you want dob't allow unicode digit use character class instead shortcut \d ( it's much faster)
\b(?:[0-9]{8}|[0-9]{13})\b

I managed to concoct this:
\b(([Ee][Aa][Nn])?[_]?([0-9]{13}|[0-9]{8}))\b
This part ([Ee][Aa][Nn])? groups the case-insensitive sequence EAN and makes it optional with ?
Then [_]? makes the underscore optional. I added the square brackets for prettiness sake
The digits are identified using their character representation [0-9]{13} and [0-9]{8}
Everything is wrapped up in a \b( ... )\b block to identify the word boundary
The two EAN types are wrapped by parentheses and separated by an OR |
Below is a screenshot from http://regexpal.com/ showing the testing set and the matching.
Jorge, I must say I don't like repeating code, (or anything else for that matter :D ). I am therefore not very fond of the whole ([Ee][Aa][Nn])?[_]? appearing twice. Moreover if tomorrow you wish to look for EAN5 for example you must further copy it and the regexp becomes ever more ugly.
Here is what I had before the cleanup:
\b(([Ee][Aa][Nn])?[_]?[0-9]{13}|([Ee][Aa][Nn])?[_]?[0-9]{8})\b
Below is a screenshot from http://regexpal.com/ showing the testing set and the matching.

Validate string based on custom format

I want to validate a string based on a custom format: ___.___ or ___,___, 3 numbers followed by a dot or comma followed by 3 numbers (e.g. 123.456 or 123,456).
Currently, I have following code:
string InputText = "123.456"
bool result, result1, result2;
int test, test2;
result = Int32.TryParse(InputText.Substring(0, 3), out test);
result1 = (InputText[3] == '.' || InputText[3] == ',') ? true : false;
result2 = Int32.TryParse(InputText.Substring(4, 3), out test2);
if (result == false || result1 == false || result2 == false)
{
Console.WriteLine("Error! Wrong format.");
}
This works just fine, however, this seems rather inefficient and unnecessarily complex; is there an alternative to this?

Is there an alternative to this? Yes you can use Regex.IsMatch to do this.
String s = "123.456";
if (!Regex.IsMatch(s, #"^\d{3}[.,]\d{3}$")) {
Console.WriteLine("Error! Wrong format.");
}
Explanation:
^ # the beginning of the string
\d{3} # digits (0-9) (3 times)
[.,] # any character of: '.', ','
\d{3} # digits (0-9) (3 times)
$ # before an optional \n, and the end of the string

Pattern to validate 3 numbers followed by a dot or comma followed by 3 numbers is,
^\d{3}[,.]\d{3}$
DEMO

Aditional to Avinash answer if you want to capture the numbers matching the format you can use the following regex:
\b(\d{3}[.,]\d{3})\b
Working demo

Replace using Regular Expression - fixed digit location

I would like to replace from a number of 16 digits, it's 5th to 10th digit.
How can that be achieved with a regular expression (C#)?

The way to do it is to capture in the inner and outer portions separately, like this:
// Split into 2 groups of 5 digits and 1 of 6
string regex = "(\\d{5})(\\d{5})(\\d{6})";
// Insert ABCDEF in the middle of
// match 1 and match 3
string replaceRegex = "${1}ABCDE${3}";
string testString = "1234567890999999";
string result = Regex.Replace(testString, regex, replaceRegex);
// result = '12345ABCDE999999'

Why use a regular expression? If by "number of 16 digits", you mean a 16 character long string representation of a number, then you'd probably be better off just using substring.
string input = "0000567890000000";
var output = input.Substring(0, 4) + "222222" + input.Substring(10, 6);
Or did you mean you want to swap the 5th and 10th digits? Your question isn't very clear.

Use the regular expression (?<=^\d{4})\d{6}(?=\d{6}$) to achieve it without capture groups.
It looks for 6 consecutive digits (5th to 10th inclusively) that are preceded by the first 4 digits and the last 6 digits of the string.
Regex.Replace("1234567890123456", #"(?<=^\d{4})\d{6}(?=\d{6}$)", "replacement");

Got it...
by creating 3 capturing groups:
([\d]{5})([\d]{5})([\d]{6})
keep capturing group1 and 3 and replace group2 with stars (or whatever)
$1*****$3
C# code below
string resultString = null;
try {
resultString = Regex.Replace(subjectString, #"([\d]{5})([\d]{5})([\d]{6})", "$1*****$2", RegexOptions.Singleline);
} catch (ArgumentException ex) {
// Syntax error in the regular expression
}

How to validate this using Regex C#

I have a input which can be the following (Either one of these three):
1-8…in other words 1, 2,3,4,5,6,7,8
A-Z….in other words, A, B, C, D etc
01-98…in other words, 01,02,03,04 etc
I came up with this regex but it's not working not sure why:
#"[A-Z0-9][1-8]-
I am thinking to check for corner cases like just 0 and just 9 after regex check because regex check isn't validating this

Not sure I understand, but how about:
^(?:[A-Z]|[1-8]|0[1-9]|[1-8][0-9]|9[0-8])$
Explanation:
(?:...) is a group without capture.
| introduces an alternative
[A-Z] means one letter
[1-8] one digit between 1 and 8
0[1-9] a 0 followed by a digit between 1 and 9
[1-8][0-9] a digit between 1 and 8 followed by a digit between 1 and 9
9[0-8] 9 followed by a digit between 0 and 8
May be it is, depending on your real needs:
^(?:[A-Z]|[0-9]?[1-8])$

I think you may use this pattern
#"^([1-8A-Z]|0[1-9]|[1-9]{2})$"

What about ^([1-8]|([0-9][0-9])|[A-Z])$ ?
That will give a match for
A
8 (but not 9)
09

[1-8]{0,1}[A-Z]{0,1}\d{1,2}
matches all of the following
8A8 8B9 9 0 00

You can use following pattern:
^[1-8][A-Z](?:0[1-9]|[1-8][0-9]|9[0-8])$
^[1-8] - input should start with number 1-8
[A-Z] - then should be single letter A-Z
(0[1-9]|[1-8][0-9]|9[0-8])$ and it should end with two numbers which are 01-19 or 10-89 or 90-98
Test:
string pattern = #"^[1-8][A-Z](0[1-9]|[1-8][0-9]|9[0-8])$";
Regex regex = new Regex(pattern);
string[] valid = { "1A01", "8Z98" };
bool allMatch = valid.All(regex.IsMatch);
string[] invalid = { "0A01", "11A01", "1A1", "1A99", "1A00", "101", "1AA01" };
bool allNotMatch = !invalid.Any(regex.IsMatch);

Regex for 6 digit int that can't be sequential or repeated digits?

I am trying to get a Regex that checks to make sure that a supplied int is 6 digits and it is not sequential nor contains all repeating digits whether in ascending or descending order. I don't really care if the regex returns a match for the non-allowed numbers, or returns a match of the original number if it is allowed.
So for example all of these numbers are what I would need to not pass validation with the regex:
123456
654321
069
456789
2435
444444
While numbers like these would pass:
044346
666605
042004
678853
Thanks.
EDIT: Appears regex is not appropriate for this. A lot of great answers and multiple are right, so I just went with who answered first, thank you all!

Regex may not be optimal for this, but it can be done with:
^
# fail if...
(?!
# repeating numbers
(\d) \1+ $
|
# sequential ascending
(?:0(?=1)|1(?=2)|2(?=3)|3(?=4)|4(?=5)|5(?=6)|6(?=7)|7(?=8)|8(?=9)|9(?=0)){5} \d $
|
# sequential descending
(?:0(?=9)|1(?=0)|2(?=1)|3(?=2)|4(?=3)|5(?=4)|6(?=5)|7(?=6)|8(?=7)|9(?=8)){5} \d $
)
# match any other combinations of 6 digits
\d{6}
$
Use with /x flag or (?x) to preserve the readability.
You can also use the compact form (not recommended):
^(?!(\d)\1+$|(?:0(?=1)|1(?=2)|2(?=3)|3(?=4)|4(?=5)|5(?=6)|6(?=7)|7(?=8)|8(?=9)|9(?=0)){5}\d$|(?:0(?=9)|1(?=0)|2(?=1)|3(?=2)|4(?=3)|5(?=4)|6(?=5)|7(?=6)|8(?=7)|9(?=8)){5}\d$)\d{6}$
Example usage (ideone):
using System;
using System.Text.RegularExpressions;
public class Test
{
public static void Main()
{
string re = #"(?x)
^
# fail if...
(?!
# repeating numbers
(\d) \1+ $
|
# sequential ascending
(?:0(?=1)|1(?=2)|2(?=3)|3(?=4)|4(?=5)|5(?=6)|6(?=7)|7(?=8)|8(?=9)|9(?=0)){5} \d $
|
# sequential descending
(?:0(?=9)|1(?=0)|2(?=1)|3(?=2)|4(?=3)|5(?=4)|6(?=5)|7(?=6)|8(?=7)|9(?=8)){5} \d $
)
# match any other combinations of 6 digits
\d{6}
$
";
string[] numbers = { "102", "111111", "123456", "654321", "123455", "321123", "111112" };
foreach (var str in numbers)
{
Console.WriteLine(str);
Console.WriteLine(Regex.IsMatch(str, re) ? "\tMatched" : "\tFailed");
}
}
}
Output:
102
Failed
111111
Failed
123456
Failed
654321
Failed
123455
Matched
321123
Matched
111112
Matched

To be honest I don't think I got what you wanted, but following code works for your cases :)
var isMatch = Regex.IsMatch(input, "^[0-9]{6}$")
&& Regex.IsMatch(input, #"(([0-9]{1})\2+)")
&& input.Distinct().Count() > 1;
After several re-reading I think I got what you want :) See the following:
var isMatch = String.Join("", input.OrderBy(c => c)) != input
&& String.Join("", input.OrderByDescending(c => c)) != input
&& input.Distinct().Count() > 1
&& Regex.IsMatch(input, "^[0-9]{6}$");

The invalid strings are so little in number that you could just do this:
using System.Xml;
using System.Linq;
using System.Collections.Generic;
using System.Text.RegularExpressions;
class Program {
static void Main(string[] args) {
string input = "124032";
string[] invalid = {
"012345",
"123456",
// ...
"000000",
"111111",
// ...
};
if (Regex.IsMatch(input, #"^\d{6}$") && !invalid.Contains(input)) {
// ok
}
}
}

Just as a reference as to why you should NOT do this. Here's a regex that would satisfy your requirements -- it's a mess:
(?!123456)(\d)(((?!\1)\d{5})|((\d)(?!\1)\d{4})|((\d){2}(?!\1)\d{3})|((\d){3}(?!\1)\d{2})|((\d){4}(?!\1)\d))
where you must expand the (?!123456) for all 20 possible iterations of repeated digits. (20 = 10 possible starting digits * (one ascending + one descending))
You start off with the negative lookahead preventing the 20 sequential digits scenarios, grab a single digit, and then do checks that require (via a negative lookeahead) that at least one digit must be different from the first digit. If it passes this, it succeeds.

That's not a elegant solution but works!
/^[0]{6}|[1]{6}|[2]{6}|[3]{6}|[4]{6}|[5]{6}|[6]{6}|[7]{6}|[8]{6}|[9]{6}$/