Zip code validation using regular expressions

[Alpha83]

Hi,
Is it safe or error-free to validate country zip-codes using regular
expressions - especially for countries like UK or Canada, where there
are different alphanumeric formats. Here's what I got for UK -
System.Text.RegularExpressions.Regex(@"^(([A-Z]{1,2}[0-9][0-9A-Z]{0,1})
\ ([0-9][A-Z]{2}))|(GIR\ 0AA)$").

Got this from regex.lib, and needed to know also if there are better
approaches for zip code validation.

Thanks.

[=?Utf-8?B?S0g=?=]

Regular expressions will work fine for something like that; my only comment
is that they can sometimes be like using a sledgehamed to drive a finishing
nail... they are sometimes (dare I say often?) overkill for what someone is
trying to accomplish.

On the other hand you can store regex patterns in resource files so they can
be changed w/o recompiling the app which could be very handy.

HTH
"Alpha83" wrote:

Hi,
Is it safe or error-free to validate country zip-codes using regular
expressions - especially for countries like UK or Canada, where there
are different alphanumeric formats. Here's what I got for UK -
System.Text.RegularExpressions.Regex(@"^(([A-Z]{1,2}[0-9][0-9A-Z]{0,1})
\ ([0-9][A-Z]{2}))|(GIR\ 0AA)$").

Got this from regex.lib, and needed to know also if there are better
approaches for zip code validation.

Thanks.

[Paul E Collins]

"Alpha83" <ta*****@gmail.comwrote:

Is it safe or error-free to validate country zip-codes using regular
expressions - especially for countries like UK or Canada, where there are
different alphanumeric formats.

I think that regular expression is about as good as you'll get for the UK,
but it's still not perfect because it permits some postcodes that don't
exist. (For example, just because there's N for North London and it's
followed by a number, there doesn't have to be an N99 region defined yet.)
Also, you need to be willing to keep it up to date, because postcodes can
change and evolve over time with building and population increases, etc.

Eq.