CODEWITHSUNDEEP
c#regexwinformsvalidationexpression
Aung Kaung Hein
Aung Kaung Hein

Reputation: 1576

Regex for validating decimal values

I am now using this regex,

Regex rg = new Regex(@"\d{1,16}\.?|\d{0,16}\.\d{1,3}");

to validate the decimal values entered into a Textbox. It works fine. But it allows a user to enter decimal values together with non-numeric characters like 2.a or 2\.

I believe that wrong portion is here \.?. I have used ? so it accepts alphabetical values? I have tried something like \.[0-9]? but it's not working.

Below are valid and invalid values:

There might be duplicate questions on SO. But valid regex tokens vary by implementation. That's why I asked a new question here. Any help will be much appreciated!

Upvotes: 0

Views: 3946

Answers (2)

Szymon
Szymon

Reputation: 43023

You can use that regex:

^\d{1,16}(\.\d{1,4})?$

It will validate first between 1 and 16 digits an optional dot and 1 to 4 digits.

If you want to always have dot, you should use:

^\d{1,16}((\.\d{1,4})|(\.))?$

Upvotes: 2

daniel.brubeck
daniel.brubeck

Reputation: 654

The regex 

^\d{1,16}(\.\d{1,4})?$

works fine, if you want to recognize if only on point you can add

^(\d{1,16})|(\d{1,16}\.{1}\d{0,4})|(\d{1,16}\.{1})$

It's not as elegant as the other but works in the scenarios you posted.

Upvotes: 1

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