CODEWITHSUNDEEP
c#regex
Robby Smet
Robby Smet

Reputation: 4661

Regex with numbers and special characters but no letters

I'm making a regex that accepts an input with any decimal(0-9), +, * or # but shouldn't accept any letters(a-z).

so numbers like

should be accepted.

The regex is invalid when there is any letter in the string.

This is the regex I have so far: 

private const string PhoneNumberRegex = "((\\d)|(\\*)|(\\#)|(\\+))?";

private bool IsValid(inputString)
{
    // Accept * # + and number
    Match match = Regex.Match(inputString, PhoneNumberRegex, RegexOptions.IgnoreCase);
    return match.Success;
}

But this regex also returns true on #192#abbef

How can I fix this?

Upvotes: 13

Views: 65331

Answers (4)

SQB
SQB

Reputation: 4078

You need to anchor your string with ^ (begin of line) and $ (end of line). Otherwise your string matches if any part of it matches.

Also, you want at least one of those characters (you don't want to match an empty string, so you should use + (one or more).

Lastly, you can make a character class out of all your characters: [\d*#+].

Putting it all together gives you:

private const string PhoneNumberRegex = "^[\\d*#+]+$";

This means that from the beginning of the string till the end, you want one or more of those characters you listed.

Upvotes: 5

I A Khan
I A Khan

Reputation: 8839

Use this :

const string MYRegex = @"^[0-9*#+]+$";

for more information plz visit

http://www.regexlib.com/Search.aspx?k=special%20characters&AspxAutoDetectCookieSupport=1

http://www.cisco.com/en/US/docs/ios_xr_sw/iosxr_r3.4/getting_started/installation/guide/gs34aexp.pdf

Upvotes: 0

Austin
Austin

Reputation: 904

I believe this will meet your needs

private const string PhoneNumberRegex = @"^([0-9]|#|\+|\*)+$"

Upvotes: 2

Casimir et Hippolyte
Casimir et Hippolyte

Reputation: 89557

You can use this:

private const string PhoneNumberRegex = @"^[0-9*#+]+$";

Where ^ and $ are anchors for start and end of the string.

Note: RegexOptions.IgnoreCase is not needed.

Upvotes: 19

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