How do I create a regular expression to accept 1-14 digits only?

Question

0.00/5 (No votes)

See more:

I know I am going to kick myself when I see the answer, but I have been playing with this for an hour and can't figure out how to write a regular expression to accept 1-14 digits in a single-line string and reject anything else. This is for use inside a WPF ValidationRule.

Note that this is not attempting to find such sub-strings in a body of text; it is intended to reject anything that does not fit the pattern, so 01234567890123 is fine but 01234567890123X is not.

What I have tried:

None of these work:

^[0-9]{1,14}$

[0-9]{1,14}$

^[0-9]{1,14}

[0-9]{1,14}

This almost works...

\b[0-9]{1,14}\b

...but for some reason will accept an open bracket, so it will match 1234(, which it should reject.

Posted 20-Jun-17 23:29pm

Patrick Skelton

Updated 20-Jun-17 23:49pm

v3

Add a Solution

Comments

Tomas Takac 21-Jun-17 5:46am

You should update your question with the code you use for testing. FYI ^[0-9]{1,14}$ works as expected for me with the examples you gave.

2 solutions

Add a Solution

Add your solution here

Treat my content as plain text, not as HTML

Preview 0

…

Existing Members

Sign in to your account

...or Join us

Download, Vote, Comment, Publish.

Your Email
Password
Forgot your password?

Your Email
This email is in use. Do you need your password?
Optional Password

I have read and agree to the Terms of Service and Privacy Policy
Please subscribe me to the CodeProject newsletters

When answering a question please:

Read the question carefully.
Understand that English isn't everyone's first language so be lenient of bad spelling and grammar.
If a question is poorly phrased then either ask for clarification, ignore it, or edit the question and fix the problem. Insults are not welcome.
Don't tell someone to read the manual. Chances are they have and don't get it. Provide an answer or move on to the next question.

Let's work to help developers, not make them feel stupid.

This content, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

Patrice T · Accepted Answer · 2017-06-20T23:44:00

Solution 1

Quote:
^[0-9]{1,14}$

This one should do. Your fail have another reason. You should give more details.

Just a few interesting links to help building and debugging RegEx.
Here is a link to RegEx documentation:
perlre - perldoc.perl.org[^]
Here is links to tools to help build RegEx and debug them:
.NET Regex Tester - Regex Storm[^]
Expresso Regular Expression Tool[^]
This one show you the RegEx as a nice graph which is really helpful to understand what is doing a RegEx:
Debuggex: Online visual regex tester. JavaScript, Python, and PCRE.[^]

Posted 20-Jun-17 23:44pm

Patrice T

Updated 20-Jun-17 23:52pm

v2

Comments

Patrick Skelton 21-Jun-17 7:19am

The expression above does indeed work as expected using the excellent Debuggex (thank you for the link). And, when I go back into code, I find that it does indeed now work as expected. Maybe I was somehow testing a different piece of code to the one I was editing. Doh! I take the earlier point by Tomas, that I should have included some test code, which would quickly have indicated that something other than the regular expression was to blame. Thank you all for the help.

Kornfeld Eliyahu Peter · Accepted Answer · 2017-06-20T23:49:00

^[0-9]{1,14}$

The problem however is about how the Regex engine interprets ^ and $...
If you are in single-line mode the engine look at the input as a single line and ^ and $ means the beginning and the end of the whole input!
In multi-line mode (/m or RegexOptions.Multiline[^]) the mmenaing of ^ and $ changes and it is now the beginning and the end of line within the whole input...

C#

Regex oRegex = new Regex("^[0-9]{1,14}$", RegexOptions.Multiline);