Regular expressions

David Smith

How do i pull the number from this string     "Emample_ColorRevA.Page1"

I want to be able to pull the number 1 using regular expressions, can someone assist me.

"Emample_ColorRevA.Page1"               Result would be 1
"Emample_ColorRevB.Page2"               Result would be 2
"Emample_ColorRevB.Page234"            Result would be 234

How can I only get the number from the strings

21 Replies

Know the answer? Post it — somebody with the same question will find it here.

Satish Bhat15y ago
Accepted answer
Try

public static string GetNumberFromString(string input)
{
// To Match number anywhere in the string e.g. Something123And234
// you will get 123 & 234
// Match _match = Regex.Match(input.Trim(), @"[0-9]+");

// Match only at the end of the string
Match _match = Regex.Match(input.Trim(), @"(\d+)$");
return (_match.Value);
}

string _input = "Emample_ColorRevB.Page234";
string _output = GetNumberFromString(_input); // 234
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David Smith15y ago
Done, I remove the check from yours
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Vulpes15y ago
The only problem is that you've checked the box on my post rather than Satish's.

If you uncheck mine and check his, then it should move the highlight to his post.
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David Smith15y ago
I feel bad now, because after all this time i have been register on c -sharp corner, I have never check that checkbox. I check both now. Sorry about that. Im glad you told me.
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Vulpes15y ago
I'll grant you that it's confusing but the 'Thumb's up' is where you (or anyone else) finds the information in a post useful.

However, there's also an 'Accepted Answer' button where the original poster (and nobody else) can mark just one post as answering the question that was posed. The answerer then gets 4 extra points which may help him or her to win one of the monthly prizes.

So, as Satish correctly answered the question as posed, he's entitled to receive an Accepted Answer in my view.

However, I'm glad you found my posts useful as well as I don't post if a question has already been answered unless I feel I have something worthwhile to add :)
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David Smith15y ago
Vuples I also gave you credit to. If I dont do nothing else in life, I will give somebody credit whether the anwser is correct or not. Because of the time and effort a person will spent.
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David Smith15y ago
I mark the answer along time ago. Do you guys not see the answer i mark. I am a little confuse. On my side the thumbs is up with 1 point. You guys still on that point. I gave where it was due along time ago.
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Satish Bhat15y ago
Thanks Vulpes for recommending my answer. Honestly it didn't come to my mind to give him a simple answer. He asked for regular expression, I gave that. to you for that and for your sportive spirit.

Although I am a registered member since 2004, I made little contribution to the site because of whatever the reasons may be. Now because of you guys I am trying to participate whenever I find time. Keep up the good work.

Vuples, you are 100% right in "there's a tendency to always reach for the driver when an iron will do". So darnell follow the KISS design principle, use the solution and mark the answer.
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Vulpes15y ago
Vulpes (when spelt correctly) is Latin for 'fox' - hence my picture ;)

Don't forget to mark Satish's post as the accepted answer.
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David Smith15y ago
Thanks, you rock.

you haven't explain vuples yet. lol
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Vulpes15y ago
\d means match any digit (0 to 9) and when followed by +, it means match one or more consecutive digits.

$ means at the end of the string, so match one or more digits at the end of the string.

The (...) are used to treat what's within the parentheses as a 'group' though it's not really necessary here.

The @ at the beginning of the string tells the C# compiler to treat what's in the string literally. This is needed as otherwise it would attempt to interpret \d as an 'escape sequence' such as \n or \t which we don't want as \d is a special symbol used in regular expressions.

The Regex.Match method says if there's a match in the string for the regular expression, then return it as a Match object. The Value property then gets the actual sub-string which is matched.
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David Smith15y ago
Can you break this down for me, so that i can understand it.

Match _match = Regex.Match(input.Trim(), @"(\d+)$");

Start from "@"(\d+)$"

I understand the input.trim()
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David Smith15y ago
What is vuples, can you show me an example
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Vulpes15y ago
LOL, they mean me - Vulpes!

A good site for learning regular expressions from the ground up is this one:

http://www.regular-expressions.info/tutorial.html
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David Smith15y ago
Vuples, I never use vuples, do you guys have an example of vuples. With the example i need help with.

Also can someone point me to good sight using regular expressions
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David Smith15y ago
Vuples, I never use vuples, do you guys have an example of vuples. With the example i need help with.

Also can someone point me to good sight using regular expressions
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David Smith15y ago
Vuples, I never use vuples, do you guys have an example of vuples. With the example i need help with
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Vulpes15y ago
The OP did ask for a regular expression solution and he should therefore mark Satish's post as the accepted answer.

The purpose of my post was to point out that there's also an easy solution using ordinary string parsing, as there's a tendency to always reach for the driver when an iron will do :)
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Satish Bhat15y ago
Yes indeed Vuples reply is more easier. I thought he is specifically asking for the regular expressions solution.
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Suthish Nair15y ago
I assume Vuples replies is more easier.
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Vulpes15y ago
If you know that the number will always be at the end of the string, there's also an easy way to do this without using regular expressions:

string s = "Emample_ColorRevB.Page234";
string number = s.Substring(s.IndexOfAny("0123456789".ToCharArray()));
Console.WriteLine(number); // 234
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