Develop Reference

How to split Alphanumeric with Symbol in C#

I want to spilt Alphanumeric with two part Alpha and numeric with special character like -
string mystring = "1- Any Thing"
I want to store like:
numberPart = 1
alphaPart = Any Thing
For this i am using Regex
Regex re = new Regex(#"([a-zA-Z]+)(\d+)");
Match result = re.Match("1- Any Thing");
string alphaPart = result.Groups[1].Value;
string numberPart = result.Groups[2].Value;
If there is no space in between string its working fine but space and symbol both alphaPart and numberPart showing null where i am doing wrong Might be Regex expression is wrong for this type of filter please suggest me on same

Try this:
(\d+)(?:[^\w]+)?([a-zA-Z\s]+)
Demo
Explanation:
(\d+) - capture one or more digit
[^\w]+ match anything except alphabets
? this tell that anything between word and number can appear or not(when not space is between them)
[a-zA-Z\s]+ match alphabets(even if between them have spaces)

Start of string is matched with ^.
Digits are matched with \d+.
Any non-alphanumeric characters are matched with [\W_] or \W.
Anything is matched with .*.
Use
(?s)^(\d+)\W*(.*)
See proof
(?s) makes . match linebreaks. So, it literally matches everything.

get number from a string after trimming 0 using Regex c#

I have a namestring like ( This is a file name stored in server)
Offer_2018-06-05_PROSP000033998_20180413165327.02155000.NML.050618.1040.67648.0
The file name format is given above. I need to get the number out of
PROSP000033998
and remove the leading zeros ( 33998) using Regex in C# . there are different values that will come instead of PROSP. So i want to use a regex to get the number instead of string split. Tried using (0|[1-9]\d*), but not sure whether this is correct as i got 2018 as the output
Regex regexLetterOfOffer = new Regex (#"0|[1-9]\d*");
Match match = regexLetterOfOffer.Match (fileInfo.Name);
if (match.Success)
{
Console.WriteLine (match.Value);
}

A generalized regular expression for alphabetical characters, possibly followed by zeros, then capturing digits with an underscore afterwards could be
[A-Z]0*([1-9]\d*)(?=_)
That is:
Regex regexLetterOfOffer = new Regex (#"[A-Z]0*([1-9]\d*)(?=_)");
Match match = regexLetterOfOffer.Match("Offer_2018-06-05_PROSP000033998_20180413165327.02155000.NML.050618.1040.67648.0");
if (match.Success)
{
Console.WriteLine (match.Groups[1].Value);
}
This will match similar strings whose digit sequences start with something other than PROSP.

Putting (0|[1-9]\d*) into https://java-regex-tester.appspot.com/ shows that it is actually matching the number you want, it's just also matching all the other numbers in the string. The Match method only returns the first one, 2018 in this case. To only match the part you're after, you could use PROSP0*([1-9]\d*) as the regex. The brackets () around the last part make it a capturing group, which you can retrieve using the Groups property of the Match object:
Console.WriteLine(match.Groups[1].Value)
(Group 0 is the whole match, hence we want group 1.)

Regex expression that match only these cases

I have a regular expression in c# that should return IsMatch = true only when the input has the desired pattern but actually is returning true if some of the characters matches...How would be the correct regular expression?
Regex reg = new Regex(#"[0-9 \-+]"); //accept only numbers, spaces, minus character and plus character
string formularight="1123 - 4432+32124";//its correct
bool validformat=reg.IsMatch(formularight)) //returns true, ok
string formulawrong="1123a - 4432+32124"; //it has one letter ismatch should be false...
validformat=reg.IsMatch(formulawrong)) //returns true, not ok
I check later if each number is followed by a minus or plus sign before the next number but if it can be included in the regex validation...
I checked other regex questions and before someone suggest that i use a datatable to compute() the expresion or use some calculator logic please know that in this case the numbers are used like fields names that i will use to get some values from the database not numerical values per se. So i only need the regex validation before parsing the formula. Thanks
Valid examples for regex:
11123
112 - 1121
112-1121
1221111+554-111135678
44332-54-114
Invalid examples (letters present, not a + or - between numbers,...):
112 -
6543e
112 1121
6543e + 4432
-7632

Your Regular Expression finds several matches, because you didn't force it to match the whole input.
By using the following anchors, it will be forced to check the entire input.
^ - Start
$ - End
Regex:
^[0-9 \-+]*$
Regexr: http://regexr.com/3b97l

How about:
^\d+(?:\s*[+-]\s*\d+)*$
This works for your valid and invalid examples.
In order to match numbers in brackets:
^\[?\d+\]?(?:\s*[+-]\s*\[?\d+\]?)*$

You should start and end anchors in your regex:
Regex reg = new Regex(#"^[0-9 +-]+$");
to make sure whole input matches given set of characters.
isMatch Reference

regular expression for 4 number, a comma and 4 numbers

Using a regular expression, I would like to match the following string:
4232,2232
I have tried
^[0-9]+(,[0-9]+)$
However, it doesn't work as expected. I want to cater for 4 numbers, a comma and 4 numbers.

You can use the following:
\d{4},\d{4} //or ^\d{4},\d{4}$ with anchors for start and end of string
Explanation:
\d{4} match digits exactly 4 times (\d is shorthand notation for [0-9])
,\d{4} followed by comma and exactly 4 digits again

If i understand you correctly the RegEx you are looking for is basically:
(\d{4},\d{4})
This matches your provided expression as one group.
As an alternative you could write:
([0-9]{4},[0-9]{4})
which has the same result.

In C#, you can use Regex.IsMatch with the \b\d{4},\d{4}\b regex:
var found_value1 = Regex.IsMatch("4232,2232", #"\b\d{4},\d{4}\b");
var found_value2 = Regex.IsMatch("12345,2232", #"\b\d{4},\d{4}\b");
\b makes sure we match whole number.
Output:
true
false

Regex to isolate a specific substring

I have this string I have retrieved from a File.ReadAllText:
6 11 rows processed
As you can see there is always an integer specifying the line number in this document. What I am interested in is the integer that comes after it and the words "rows processed". So in this case I am only interested in the substring "11 rows processed".
So, knowing that each line will start with an integer and then some white space, I need to be able to isolate the integer that follows it and the words "rows processed" and return that to a string by itself.
I have been told this is easy to do with Regex, but so far I haven't the faintest clue how to build it.

You don't need regular expressions for this. Just split on the whitespace:
var fields = s.Split(new char[0], StringSplitOptions.RemoveEmptyEntries);
Console.WriteLine(String.Join(" ", fields.Skip(1));
Here, I am using the fact that if you pass an empty array as the char [] parameter to String.Split, it splits on all whitespace.

This should work for what you need:
\d+(.*)
This searches for 1 or more digits (\d+) and then it puts everything afterwards in a group:
. = any character
* = repeater (zero or more of the preceding value (which is any character in the above
() = grouping
However, Jason is correct in that you only need to use a split function

If you need to use a Regex it would be like this:
string result = null;
Match match = Regex.Match(row, #"^\s*\d+\s*(.*)");
if (match.Success)
result = match.Groups[1].Value;
The regex matches from start of row: first spaces if any, then digits and then more spaces. Last it extracts rest of line and return it as result.

This is done easily with Regex.Replace() using the following regular expression...
^\d+\s+
So it'd be something like this:
return Regex.Replace(text, #"^\d+\s+", "");
Basically you're just trimming the first number \d and the whitespace \s that follows.

Example in PHP(C# regex should be compatible):
$line = "6 11 rows processed";
$resp = preg_match("/[0-9]+\s+(.*)/",$line,$out);
echo $out[1];
I hope I catched your point.