Valid UK Postcode Regex Pattern?

Question

I have been given the following pattern for a UK Postcode:

([A-PR-UWYZ0-9][A-HK-Y0-9][AEHMNPRTVXY0-9]?[ABEHMNPRVWXY0-9]? {1,2}[0-9][ABD-HJLN-UW-Z]{2}|GIR 0AA)

Can anyone break this down for me?

Spending US$40 on Windows regexbuddy is imo well worth the dollars. I run it on Linux/Mac under wine just fine, and since it all rhymes it must be good ;) — gwillie, Jan 06 '14 at 22:05
If you're using PHP, you might check this [non-regex solution](http://stackoverflow.com/questions/15960184/united-kingdom-gb-postal-code-validation-without-regex/16303815#16303815). — HamZa, Jan 06 '14 at 22:18

score 3 · Answer 1 · answered Jan 06 '14 at 22:03

Here it is:

NODE                     EXPLANATION
----------------------------------------------------------------------
  (                        group and capture to \1:
----------------------------------------------------------------------
    [A-PR-UWYZ0-9]           any character of: 'A' to 'P', 'R' to
                             'U', 'W', 'Y', 'Z', '0' to '9'
----------------------------------------------------------------------
    [A-HK-Y0-9]              any character of: 'A' to 'H', 'K' to
                             'Y', '0' to '9'
----------------------------------------------------------------------
    [AEHMNPRTVXY0-9]?        any character of: 'A', 'E', 'H', 'M',
                             'N', 'P', 'R', 'T', 'V', 'X', 'Y', '0'
                             to '9' (optional (matching the most
                             amount possible))
----------------------------------------------------------------------
    [ABEHMNPRVWXY0-9]?       any character of: 'A', 'B', 'E', 'H',
                             'M', 'N', 'P', 'R', 'V', 'W', 'X', 'Y',
                             '0' to '9' (optional (matching the most
                             amount possible))
----------------------------------------------------------------------
     {1,2}                   ' ' (between 1 and 2 times (matching the
                             most amount possible))
----------------------------------------------------------------------
    [0-9]                    any character of: '0' to '9'
----------------------------------------------------------------------
    [ABD-HJLN-UW-Z]{2}       any character of: 'A', 'B', 'D' to 'H',
                             'J', 'L', 'N' to 'U', 'W' to 'Z' (2
                             times)
----------------------------------------------------------------------
   |                        OR
----------------------------------------------------------------------
    GIR 0AA                  'GIR 0AA'
----------------------------------------------------------------------
  )                        end of \1

score 2 · Answer 2 · answered Jan 06 '14 at 22:01

2

debuggex.com is a really useful resource for debugging regular expressions:

Debuggex Demo

answered Jan 06 '14 at 22:01

Digital Trauma

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score 1 · Accepted Answer · edited May 23 '17 at 11:49

1

I'm actually a bigger fan of either of the other two answers than the ones I'm about to list, but the more the merrier:

http://regex101.com/ - will give a good breakdown/explanation

http://www.regexper.com/ - will produce a lovely railroad diagram:

enter image description here

The following answers are also worth a read for slight alternatives/explanations:

UK Postcode Regex (Comprehensive)

UK Postcode Regex

edited May 23 '17 at 11:49

Community

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answered Jan 06 '14 at 22:06

Chris

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These are all amazing, but for sheer volume, I will mark you as correct. Thank you everyone! – Chud37 Jan 06 '14 at 22:13

Valid UK Postcode Regex Pattern?

3 Answers3