What's wrong with my Regex expression

Question

I have a written a Regex to check whether the string consists of 9 digits or not as follows but this always returning me false even if I have my string as 123456789.

if (Regex.IsMatch(strSSN, " ^\\d{9}$"))

Can any one tell what's wrong and also if any better one provide me .. What i am achieving is the string should have only numeric data and the length should be =9

Tim Pietzcker · Accepted Answer · 2011-11-25 15:09:11Z

5

Spaces are significant in regular expressions (and of course, you can't match a space character before the start of the string). Remove it and everything should be fine:

if (Regex.IsMatch(strSSN, "^\\d{9}$"))

Also, you generally want to use verbatim strings for regexes in C#, so you don't have to double your backslashes, but this is just a convenience, not the reason for your problem:

if (Regex.IsMatch(strSSN, @"^\d{9}$"))

edited Nov 25, 2011 at 15:09

answered Nov 25, 2011 at 14:53

Tim Pietzcker

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olly_uk · Accepted Answer · 2011-11-25 14:53:31Z

0

this should work

^\d{9}$

hope that helps

answered Nov 25, 2011 at 14:53

olly_uk

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Darin Dimitrov · Accepted Answer · 2011-11-25 14:53:55Z

0

You have a whitespace between " and ^. It should be:

if (Regex.IsMatch(strSSN, "^\\d{9}$"))

answered Nov 25, 2011 at 14:53

Darin Dimitrov

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Sam Holder · Accepted Answer · 2011-11-25 14:54:05Z

0

could it be the space at the beginning of your pattern? That seems wierd, a space then a number anchored to the start of the line.

This should give you what you want:

if (Regex.IsMatch(strSSN, "^\\d{9}$"))

answered Nov 25, 2011 at 14:54

Sam Holder

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