How to program regex to include space in C#

Question

I have a regex, which is suppose to validate strings like R1 AND R2 or R1 AND R3 OR R2 AND R4.

This is my regex:

^[R\d+ (\bAND\b|\bOR\b)]+ R\d+$

Today, I found out that it also accepts strings like "R1AND R2" or "R1 ANDR R2". How can I make sure that my regex must detect spaces between the R\d, AND and OR?

Thanks!

Toto · Accepted Answer · 2014-12-30 10:53:34Z

3

You're using a character class, it's wrong, use a non capture group instead:

^(?:R\d+\s(?:AND|OR)\s+)*R\d+$

answered Dec 30, 2014 at 10:53

Toto

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Paulo Morgado Over a year ago

If you want to explicitly only allow the space character and not all white spaces, use \x20 instead of \s.

vks · Accepted Answer · 2014-12-30 11:11:56Z

1

^R\d+(?:\s+(?:AND|OR)\s+R\d+)*$

Try this.See demo.

https://regex101.com/r/rU8yP6/4

The reaosn yours is not working is because you have included evrything inside [] character class which does not maintian sequence and is just a pool of characters to chose from.

This will match R1 AND R3 OR R2 AND R4 and R1 AND R3 but not R1AND R3

edited Dec 30, 2014 at 11:11

answered Dec 30, 2014 at 10:53

vks

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1 Comment

Dhinnesh Jeevan Over a year ago

Nice grouping :) Thanks!

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