Regular Expressions

[nibsy]

I am trying to validate an English postcode of the form XXXX XXX using regular expressions.

 

I think I may have something wrong with my pattern. I am new to regular expressions and would appreciate if somebody could point out any glaring errors.

 

Dim pattern As String = "^\s*(\d{4}\s+\d{3})\s*$"

If Not Regex.IsMatch(txtPC.Text, pattern) Then

' Do Stuff

End If

[\VB]

 

Thanks in advance.

[Hamburger1984]

I don't know what the Input looks like (whether the postcode is between other words or not) but try it without the "^" and "$"... another point: the "Not" in you If-Clause... was that an accident? ;) or did I just not understand what you're trying to do? :D

 

Andreas

[Nerseus]

I'm not sure of the English format, but in the US the last 4 digits (not 3) are optional. If the last 3 are optional, you could change the expression.

 

Otherwise, it looks good. Personally, I'm not sure I'd want the "\s*" portions, as you'll have to manually trim off the whitespace to see the "real" data. I hate trimming, but it may be necessary for you. :)

 

-Nerseus

[nibsy]

Thanks for the replies.

 

(Hamburger1984: The NOT in the IF clause only sets a boolean, as I intend to validate numerous input boxes :) )

 

Sorry, it appears I was testing the expression wrong!

 

Also, I needed to expand my expression somewhat to fully validate English post codes.

 

Here is the pattern I am using;

 

Dim pattern As String = "[A-Z]{1,2}\d{1,2}\s?\d[A-Z]{2}"

Edited July 24, 2003 by nibsy

[reanjr]

I just want to make sure you know that that pattern will match the following string:

 

...RUNDLL32 1ST PROBLEM I FORESEE...

 

It will match the "LL32 1ST" part of it

 

If you would like to make it a bit more robust, you might want:

 

\b[A-Z]{1,2}\d{1,2}\s{1,3}\d[A-Z]{2}\b

 

I'm not familiar with the English post codes, but are all of the following valid? These would all be caught by the expression

 

A1 2BC

DE3 4FG

H56 7IJ

KL89 0MN

[nibsy]

Thanks for the advice.

 

Yes, post codes of those forms would be valid. :)