RegEx pour faire correspondre les codes postaux britanniques
https://stackoverflow.com/questions/164979
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03-07-2019 - |
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Je suis après une expression rationnelle qui validera un code postal britannique complet et complexe uniquement dans une chaîne d'entrée. Tous les formulaires de codes postaux peu communs doivent être couverts ainsi que d'habitude. Par exemple:
Correspondances
- CW3 9SS
- SE5 0EG
- SE50EG
- se5 0eg
- WC2H 7LT
Pas de correspondance
- aWC2H 7LT
- WC2H 7LTa
- WC2H
Comment résoudre ce problème?
La solution
Je vous conseillerais de consulter le standard de données du gouvernement britannique pour les codes postaux [lien maintenant mort; archive de XML , voir Wikipedia pour en savoir plus]. Il existe une brève description des données et le schéma XML attaché fournit une expression régulière. Ce n'est peut-être pas exactement ce que vous voulez, mais ce serait un bon point de départ. Le RegEx diffère légèrement du XML, puisqu'un caractère P en troisième position du format A9A 9AA est autorisé par la définition donnée.
Le RegEx fourni par le gouvernement britannique était le suivant:
([Gg][Ii][Rr] 0[Aa]{2})|((([A-Za-z][0-9]{1,2})|(([A-Za-z][A-Ha-hJ-Yj-y][0-9]{1,2})|(([A-Za-z][0-9][A-Za-z])|([A-Za-z][A-Ha-hJ-Yj-y][0-9][A-Za-z]?))))\s?[0-9][A-Za-z]{2})
Comme indiqué dans la discussion sur Wikipedia, cela autorisera certains codes postaux non réels (par exemple, ceux commençant par AA, ZY) et ils fournissent un test plus rigoureux que vous pourriez essayer.
Autres conseils
Il semble que nous allons utiliser ^ (GIR? 0AA | [A-PR-UWYZ] ([0-9] {1,2} | ([A-HK-Y] [ 0-9] ([0-9ABEHMNPRV-Y])?) | [0-9] [A-HJKPS-UW])? [0-9] [ABD-HJLNP-UW-Z] {2}) $ , qui est une version légèrement modifiée de celle proposée par Minglis ci-dessus.
Cependant, nous devrons examiner exactement quelles sont les règles, car les différentes solutions énumérées ci-dessus semblent appliquer des règles différentes en ce qui concerne les lettres autorisées.
Après quelques recherches, nous avons trouvé quelques informations supplémentaires. Apparemment, une page sur 'govtalk.gov.uk' vous indique une spécification de code postal govtalk-codes postaux . Cela pointe vers un schéma XML dans le schéma XML , qui fournit une déclaration 'pseudo regex' des règles de code postal.
Nous avons pris cela et travaillé un peu pour nous donner l'expression suivante:
^((GIR &0AA)|((([A-PR-UWYZ][A-HK-Y]?[0-9][0-9]?)|(([A-PR-UWYZ][0-9][A-HJKSTUW])|([A-PR-UWYZ][A-HK-Y][0-9][ABEHMNPRV-Y]))) &[0-9][ABD-HJLNP-UW-Z]{2}))$
Cela rend les espaces facultatifs, mais vous limite à un espace (remplacez le '& amp;' par '{0,} pour les espaces illimités). Cela suppose que tout le texte doit être en majuscule.
Si vous souhaitez autoriser les minuscules, avec un nombre d'espaces quelconque, utilisez:
^(([gG][iI][rR] {0,}0[aA]{2})|((([a-pr-uwyzA-PR-UWYZ][a-hk-yA-HK-Y]?[0-9][0-9]?)|(([a-pr-uwyzA-PR-UWYZ][0-9][a-hjkstuwA-HJKSTUW])|([a-pr-uwyzA-PR-UWYZ][a-hk-yA-HK-Y][0-9][abehmnprv-yABEHMNPRV-Y]))) {0,}[0-9][abd-hjlnp-uw-zABD-HJLNP-UW-Z]{2}))$
Cela ne couvre pas les territoires d'outre-mer et n'applique que le format, PAS l'existence de zones différentes. Il est basé sur les règles suivantes:
Peut accepter les formats suivants:
- “GIR 0AA”
- A9 9ZZ
- A99 9ZZ
- AB9 9ZZ
- AB99 9ZZ
- A9C 9ZZ
- AD9E 9ZZ
Où:
- 9 peut être n'importe quel nombre à un chiffre.
- A peut être n'importe quelle lettre sauf Q, V ou X.
- B peut être n'importe quelle lettre sauf I, J ou Z.
- C peut être n’importe quelle lettre sauf I, L, M, N, O, P, Q, R, V, X, Y ou Z.
- D peut être n’importe quelle lettre sauf I, J ou Z.
- E peut être n’importe quel A, B, E, H, M, N, P, R, V, W, X ou Y.
- Z peut être n’importe quelle lettre sauf C, I, K, M, O ou V.
Meilleurs voeux
Colin
Il n’existe pas d’expression régulière complète de code postal britannique permettant de valider un code postal. Vous pouvez vérifier que le code postal est au bon format en utilisant une expression régulière. pas qu'il existe réellement.
Les codes postaux sont arbitrairement complexes et changent constamment. Par exemple, le code de sortie W1 n’a pas et ne peut jamais avoir un nombre compris entre 1 et 99 pour chaque zone de code postal.
Vous ne pouvez pas vous attendre à ce que ce qui existe actuellement soit vrai pour toujours. Par exemple, en 1990, le bureau de poste a décidé qu’Aberdeen commençait à être un peu encombré. Ils ont ajouté un 0 à la fin de AB1-5, ce qui en fait un AB10-50, puis ont créé un certain nombre de codes postaux entre ceux-ci.
Chaque fois qu'une nouvelle rue est construite, un nouveau code postal est créé. Cela fait partie du processus d'obtention de la permission de construire; les autorités locales sont obligées de tenir ces informations à jour avec la poste (elles ne le font pas toutes).
De plus, comme le signalent un certain nombre d’autres utilisateurs, il existe des codes postaux spéciaux tels que Girobank, GIR 0AA et celui destiné aux lettres au père Noël, SAN TA1 - vous ne voulez probablement rien y poster, mais cela ne veut pas. ne semble pas être couvert par une autre réponse.
Ensuite, il y a les codes postaux BFPO, qui sont désormais passer à un format plus standard . Les deux formats vont être valables. Enfin, il y a les territoires d'outre-mer la source Wikipedia . .
+----------+----------------------------------------------+ | Postcode | Location | +----------+----------------------------------------------+ | AI-2640 | Anguilla | | ASCN 1ZZ | Ascension Island | | STHL 1ZZ | Saint Helena | | TDCU 1ZZ | Tristan da Cunha | | BBND 1ZZ | British Indian Ocean Territory | | BIQQ 1ZZ | British Antarctic Territory | | FIQQ 1ZZ | Falkland Islands | | GX11 1AA | Gibraltar | | PCRN 1ZZ | Pitcairn Islands | | SIQQ 1ZZ | South Georgia and the South Sandwich Islands | | TKCA 1ZZ | Turks and Caicos Islands | +----------+----------------------------------------------+
Ensuite, vous devez prendre en compte le fait que le Royaume-Uni " exporté " son système de code postal à de nombreux endroits dans le monde. Tout ce qui valide un " UK " code postal validera également les codes postaux de plusieurs autres pays.
Si vous souhaitez valider un code postal britannique, le moyen le plus sûr consiste à utiliser une recherche des codes postaux actuels. Il y a plusieurs options:
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Ordnance Survey publie les ouverture de code-point sous une licence de données ouverte. Ce sera très légèrement en retard, mais c'est gratuit. Cela n'inclura (probablement - je ne me souviens plus) d’informations relatives à l’Irlande du Nord, car l’Ordnance Survey n’a aucun mandat à cet égard. La cartographie en Irlande du Nord est réalisée par l'Ordnance Survey of Northern Ireland et a, Pointeur . Vous pouvez utiliser ceci et ajouter les quelques-uns qui ne sont pas couverts assez facilement.
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Royal Mail publie le fichier d'adresse postale (PAF) , ce qui inclut le code BFPO pas sûr que Code-Point Open le fasse. Il est mis à jour régulièrement, mais coûte de l'argent (et parfois, il peut être très méchant). PAF inclut l’adresse complète plutôt que les seuls codes postaux et est accompagné de ses propres Programmeurs Guide . Le groupe d'utilisateurs de données ouvertes (ODUG) fait actuellement pression pour que PAF soit libéré gratuitement, voici une description de leur position .
-
Enfin, il existe AddressBase . Il s’agit d’une collaboration entre Ordnance Survey, les autorités locales, Royal Mail et une société correspondante afin de créer un répertoire définitif de toutes les informations sur toutes les adresses britanniques (elles ont également eu un assez bon succès). C'est payé, mais si vous travaillez avec une autorité locale, un ministère ou un service gouvernemental, son utilisation est gratuite. Il y a beaucoup plus d'informations que juste les codes postaux inclus.
I recently posted an answer to this question on UK postcodes for the R language. I discovered that the UK Government's regex pattern is incorrect and fails to properly validate some postcodes. Unfortunately, many of the answers here are based on this incorrect pattern.
I'll outline some of these issues below and provide a revised regular expression that actually works.
Note
My answer (and regular expressions in general):
- Only validates postcode formats.
- Does not ensure that a postcode legitimately exists.
- For this, use an appropriate API! See Ben's answer for more info.
If you don't care about the bad regex and just want to skip to the answer, scroll down to the Answer section.
The Bad Regex
The regular expressions in this section should not be used.
This is the failing regex that the UK government has provided developers (not sure how long this link will be up, but you can see it in their Bulk Data Transfer documentation):
^([Gg][Ii][Rr] 0[Aa]{2})|((([A-Za-z][0-9]{1,2})|(([A-Za-z][A-Ha-hJ-Yj-y][0-9]{1,2})|(([AZa-z][0-9][A-Za-z])|([A-Za-z][A-Ha-hJ-Yj-y][0-9]?[A-Za-z]))))[0-9][A-Za-z]{2})$
Problems
Problem 1 - Copy/Paste
As many developers likely do, they copy/paste code (especially regular expressions) and paste them expecting them to work. While this is great in theory, it fails in this particular case because copy/pasting from this document actually changes one of the characters (a space) into a newline character as shown below:
^([Gg][Ii][Rr] 0[Aa]{2})|((([A-Za-z][0-9]{1,2})|(([A-Za-z][A-Ha-hJ-Yj-y][0-9]{1,2})|(([AZa-z][0-9][A-Za-z])|([A-Za-z][A-Ha-hJ-Yj-y][0-9]?[A-Za-z]))))
[0-9][A-Za-z]{2})$
The first thing most developers will do is just erase the newline without thinking twice. Now the regex won't match postcodes with spaces in them (other than the GIR 0AA postcode).
To fix this issue, the newline character should be replaced with the space character:
^([Gg][Ii][Rr] 0[Aa]{2})|((([A-Za-z][0-9]{1,2})|(([A-Za-z][A-Ha-hJ-Yj-y][0-9]{1,2})|(([AZa-z][0-9][A-Za-z])|([A-Za-z][A-Ha-hJ-Yj-y][0-9]?[A-Za-z])))) [0-9][A-Za-z]{2})$
^
Problem 2 - Boundaries
^([Gg][Ii][Rr] 0[Aa]{2})|((([A-Za-z][0-9]{1,2})|(([A-Za-z][A-Ha-hJ-Yj-y][0-9]{1,2})|(([AZa-z][0-9][A-Za-z])|([A-Za-z][A-Ha-hJ-Yj-y][0-9]?[A-Za-z])))) [0-9][A-Za-z]{2})$
^^ ^ ^ ^^
The postcode regex improperly anchors the regex. Anyone using this regex to validate postcodes might be surprised if a value like fooA11 1AA gets through. That's because they've anchored the start of the first option and the end of the second option (independently of one another), as pointed out in the regex above.
What this means is that ^ (asserts position at start of the line) only works on the first option ([Gg][Ii][Rr] 0[Aa]{2}), so the second option will validate any strings that end in a postcode (regardless of what comes before).
Similarly, the first option isn't anchored to the end of the line $, so GIR 0AAfoo is also accepted.
^([Gg][Ii][Rr] 0[Aa]{2})|((([A-Za-z][0-9]{1,2})|(([A-Za-z][A-Ha-hJ-Yj-y][0-9]{1,2})|(([AZa-z][0-9][A-Za-z])|([A-Za-z][A-Ha-hJ-Yj-y][0-9]?[A-Za-z]))))[0-9][A-Za-z]{2})$
To fix this issue, both options should be wrapped in another group (or non-capturing group) and the anchors placed around that:
^(([Gg][Ii][Rr] 0[Aa]{2})|((([A-Za-z][0-9]{1,2})|(([A-Za-z][A-Ha-hJ-Yj-y][0-9]{1,2})|(([AZa-z][0-9][A-Za-z])|([A-Za-z][A-Ha-hJ-Yj-y][0-9]?[A-Za-z])))) [0-9][A-Za-z]{2}))$
^^ ^^
Problem 3 - Improper Character Set
^([Gg][Ii][Rr] 0[Aa]{2})|((([A-Za-z][0-9]{1,2})|(([A-Za-z][A-Ha-hJ-Yj-y][0-9]{1,2})|(([AZa-z][0-9][A-Za-z])|([A-Za-z][A-Ha-hJ-Yj-y][0-9]?[A-Za-z])))) [0-9][A-Za-z]{2})$
^^
The regex is missing a - here to indicate a range of characters. As it stands, if a postcode is in the format ANA NAA (where A represents a letter and N represents a number), and it begins with anything other than A or Z, it will fail.
That means it will match A1A 1AA and Z1A 1AA, but not B1A 1AA.
To fix this issue, the character - should be placed between the A and Z in the respective character set:
^([Gg][Ii][Rr] 0[Aa]{2})|((([A-Za-z][0-9]{1,2})|(([A-Za-z][A-Ha-hJ-Yj-y][0-9]{1,2})|(([A-Za-z][0-9][A-Za-z])|([A-Za-z][A-Ha-hJ-Yj-y][0-9]?[A-Za-z])))) [0-9][A-Za-z]{2})$
^
Problem 4 - Wrong Optional Character Set
^([Gg][Ii][Rr] 0[Aa]{2})|((([A-Za-z][0-9]{1,2})|(([A-Za-z][A-Ha-hJ-Yj-y][0-9]{1,2})|(([AZa-z][0-9][A-Za-z])|([A-Za-z][A-Ha-hJ-Yj-y][0-9]?[A-Za-z])))) [0-9][A-Za-z]{2})$
^
I swear they didn't even test this thing before publicizing it on the web. They made the wrong character set optional. They made [0-9] option in the fourth sub-option of option 2 (group 9). This allows the regex to match incorrectly formatted postcodes like AAA 1AA.
To fix this issue, make the next character class optional instead (and subsequently make the set [0-9] match exactly once):
^([Gg][Ii][Rr] 0[Aa]{2})|((([A-Za-z][0-9]{1,2})|(([A-Za-z][A-Ha-hJ-Yj-y][0-9]{1,2})|(([AZa-z][0-9][A-Za-z])|([A-Za-z][A-Ha-hJ-Yj-y][0-9][A-Za-z]?)))) [0-9][A-Za-z]{2})$
^
Problem 5 - Performance
Performance on this regex is extremely poor. First off, they placed the least likely pattern option to match GIR 0AA at the beginning. How many users will likely have this postcode versus any other postcode; probably never? This means every time the regex is used, it must exhaust this option first before proceeding to the next option. To see how performance is impacted check the number of steps the original regex took (35) against the same regex after having flipped the options (22).
The second issue with performance is due to the way the entire regex is structured. There's no point backtracking over each option if one fails. The way the current regex is structured can greatly be simplified. I provide a fix for this in the Answer section.
Problem 6 - Spaces
This may not be considered a problem, per se, but it does raise concern for most developers. The spaces in the regex are not optional, which means the users inputting their postcodes must place a space in the postcode. This is an easy fix by simply adding ? after the spaces to render them optional. See the Answer section for a fix.
Answer
1. Fixing the UK Government's Regex
Fixing all the issues outlined in the Problems section and simplifying the pattern yields the following, shorter, more concise pattern. We can also remove most of the groups since we're validating the postcode as a whole (not individual parts):
^([A-Za-z][A-Ha-hJ-Yj-y]?[0-9][A-Za-z0-9]? ?[0-9][A-Za-z]{2}|[Gg][Ii][Rr] ?0[Aa]{2})$
This can further be shortened by removing all of the ranges from one of the cases (upper or lower case) and using a case-insensitive flag. Note: Some languages don't have one, so use the longer one above. Each language implements the case-insensitivity flag differently.
^([A-Z][A-HJ-Y]?[0-9][A-Z0-9]? ?[0-9][A-Z]{2}|GIR ?0A{2})$
Shorter again replacing [0-9] with \d (if your regex engine supports it):
^([A-Z][A-HJ-Y]?\d[A-Z\d]? ?\d[A-Z]{2}|GIR ?0A{2})$
2. Simplified Patterns
Without ensuring specific alphabetic characters, the following can be used (keep in mind the simplifications from 1. Fixing the UK Government's Regex have also been applied here):
^([A-Z]{1,2}\d[A-Z\d]? ?\d[A-Z]{2}|GIR ?0A{2})$
And even further if you don't care about the special case GIR 0AA:
^[A-Z]{1,2}\d[A-Z\d]? ?\d[A-Z]{2}$
3. Complicated Patterns
I would not suggest over-verification of a postcode as new Areas, Districts and Sub-districts may appear at any point in time. What I will suggest potentially doing, is added support for edge-cases. Some special cases exist and are outlined in this Wikipedia article.
Here are complex regexes that include the subsections of 3. (3.1, 3.2, 3.3).
In relation to the patterns in 1. Fixing the UK Government's Regex:
^(([A-Z][A-HJ-Y]?\d[A-Z\d]?|ASCN|STHL|TDCU|BBND|[BFS]IQQ|PCRN|TKCA) ?\d[A-Z]{2}|BFPO ?\d{1,4}|(KY\d|MSR|VG|AI)[ -]?\d{4}|[A-Z]{2} ?\d{2}|GE ?CX|GIR ?0A{2}|SAN ?TA1)$
And in relation to 2. Simplified Patterns:
^(([A-Z]{1,2}\d[A-Z\d]?|ASCN|STHL|TDCU|BBND|[BFS]IQQ|PCRN|TKCA) ?\d[A-Z]{2}|BFPO ?\d{1,4}|(KY\d|MSR|VG|AI)[ -]?\d{4}|[A-Z]{2} ?\d{2}|GE ?CX|GIR ?0A{2}|SAN ?TA1)$
3.1 British Overseas Territories
The Wikipedia article currently states (some formats slightly simplified):
AI-1111: AnguilaASCN 1ZZ: Ascension IslandSTHL 1ZZ: Saint HelenaTDCU 1ZZ: Tristan da CunhaBBND 1ZZ: British Indian Ocean TerritoryBIQQ 1ZZ: British Antarctic TerritoryFIQQ 1ZZ: Falkland IslandsGX11 1ZZ: GibraltarPCRN 1ZZ: Pitcairn IslandsSIQQ 1ZZ: South Georgia and the South Sandwich IslandsTKCA 1ZZ: Turks and Caicos IslandsBFPO 11: Akrotiri and DhekeliaZZ 11&GE CX: Bermuda (according to this document)KY1-1111: Cayman Islands (according to this document)VG1111: British Virgin Islands (according to this document)MSR 1111: Montserrat (according to this document)
An all-encompassing regex to match only the British Overseas Territories might look like this:
^((ASCN|STHL|TDCU|BBND|[BFS]IQQ|GX\d{2}|PCRN|TKCA) ?\d[A-Z]{2}|(KY\d|MSR|VG|AI)[ -]?\d{4}|(BFPO|[A-Z]{2}) ?\d{2}|GE ?CX)$
3.2 British Forces Post Office
Although they've been recently changed it to better align with the British postcode system to BF# (where # represents a number), they're considered optional alternative postcodes. These postcodes follow(ed) the format of BFPO, followed by 1-4 digits:
^BFPO ?\d{1,4}$
3.3 Santa?
There's another special case with Santa (as mentioned in other answers): SAN TA1 is a valid postcode. A regex for this is very simply:
^SAN ?TA1$
I had a look into some of the answers above and I'd recommend against using the pattern from @Dan's answer (c. Dec 15 '10), since it incorrectly flags almost 0.4% of valid postcodes as invalid, while the others do not.
Ordnance Survey provide service called Code Point Open which:
contains a list of all the current postcode units in Great Britain
I ran each of the regexs above against the full list of postcodes (Jul 6 '13) from this data using grep:
cat CSV/*.csv |
# Strip leading quotes
sed -e 's/^"//g' |
# Strip trailing quote and everything after it
sed -e 's/".*//g' |
# Strip any spaces
sed -E -e 's/ +//g' |
# Find any lines that do not match the expression
grep --invert-match --perl-regexp "$pattern"
There are 1,686,202 postcodes total.
The following are the numbers of valid postcodes that do not match each $pattern:
'^([A-PR-UWYZ0-9][A-HK-Y0-9][AEHMNPRTVXY0-9]?[ABEHMNPRVWXY0-9]?[0-9][ABD-HJLN-UW-Z]{2}|GIR 0AA)$'
# => 6016 (0.36%)
'^(GIR ?0AA|[A-PR-UWYZ]([0-9]{1,2}|([A-HK-Y][0-9]([0-9ABEHMNPRV-Y])?)|[0-9][A-HJKPS-UW]) ?[0-9][ABD-HJLNP-UW-Z]{2})$'
# => 0
'^GIR[ ]?0AA|((AB|AL|B|BA|BB|BD|BH|BL|BN|BR|BS|BT|BX|CA|CB|CF|CH|CM|CO|CR|CT|CV|CW|DA|DD|DE|DG|DH|DL|DN|DT|DY|E|EC|EH|EN|EX|FK|FY|G|GL|GY|GU|HA|HD|HG|HP|HR|HS|HU|HX|IG|IM|IP|IV|JE|KA|KT|KW|KY|L|LA|LD|LE|LL|LN|LS|LU|M|ME|MK|ML|N|NE|NG|NN|NP|NR|NW|OL|OX|PA|PE|PH|PL|PO|PR|RG|RH|RM|S|SA|SE|SG|SK|SL|SM|SN|SO|SP|SR|SS|ST|SW|SY|TA|TD|TF|TN|TQ|TR|TS|TW|UB|W|WA|WC|WD|WF|WN|WR|WS|WV|YO|ZE)(\d[\dA-Z]?[ ]?\d[ABD-HJLN-UW-Z]{2}))|BFPO[ ]?\d{1,4}$'
# => 0
Of course, these results only deal with valid postcodes that are incorrectly flagged as invalid. So:
'^.*$'
# => 0
I'm saying nothing about which pattern is the best regarding filtering out invalid postcodes.
^([A-PR-UWYZ0-9][A-HK-Y0-9][AEHMNPRTVXY0-9]?[ABEHMNPRVWXY0-9]? {1,2}[0-9][ABD-HJLN-UW-Z]{2}|GIR 0AA)$
Regular expression to match valid UK postcodes. In the UK postal system not all letters are used in all positions (the same with vehicle registration plates) and there are various rules to govern this. This regex takes into account those rules. Details of the rules: First half of postcode Valid formats [A-Z][A-Z][0-9][A-Z] [A-Z][A-Z][0-9][0-9] [A-Z][0-9][0-9] [A-Z][A-Z][0-9] [A-Z][A-Z][A-Z] [A-Z][0-9][A-Z] [A-Z][0-9] Exceptions Position - First. Contraint - QVX not used Position - Second. Contraint - IJZ not used except in GIR 0AA Position - Third. Constraint - AEHMNPRTVXY only used Position - Forth. Contraint - ABEHMNPRVWXY Second half of postcode Valid formats [0-9][A-Z][A-Z] Exceptions Position - Second and Third. Contraint - CIKMOV not used
Most of the answers here didn't work for all the postcodes I have in my database. I finally found one that validates with all, using the new regex provided by the government:
It isn't in any of the previous answers so I post it here in case they take the link down:
^([Gg][Ii][Rr] 0[Aa]{2})|((([A-Za-z][0-9]{1,2})|(([A-Za-z][A-Ha-hJ-Yj-y][0-9]{1,2})|(([A-Za-z][0-9][A-Za-z])|([A-Za-z][A-Ha-hJ-Yj-y][0-9]?[A-Za-z])))) [0-9][A-Za-z]{2})$
UPDATE: Updated regex as pointed by Jamie Bull. Not sure if it was my error copying or it was an error in the government's regex, the link is down now...
UPDATE: As ctwheels found, this regex works with the javascript regex flavor. See his comment for one that works with the pcre (php) flavor.
According to this Wikipedia table
This pattern cover all the cases
(?:[A-Za-z]\d ?\d[A-Za-z]{2})|(?:[A-Za-z][A-Za-z\d]\d ?\d[A-Za-z]{2})|(?:[A-Za-z]{2}\d{2} ?\d[A-Za-z]{2})|(?:[A-Za-z]\d[A-Za-z] ?\d[A-Za-z]{2})|(?:[A-Za-z]{2}\d[A-Za-z] ?\d[A-Za-z]{2})
When using it on Android\Java use \\d
An old post but still pretty high in google results so thought I'd update. This Oct 14 doc defines the UK postcode regular expression as:
^([Gg][Ii][Rr] 0[Aa]{2})|((([A-Za-z][0-9]{1,2})|(([A-Za-z][A-Ha-hJ-Yj-y][0-9]{1,2})|(([**AZ**a-z][0-9][A-Za-z])|([A-Za-z][A-Ha-hJ-Yj-y][0-9]?[A-Za-z])))) [0-9][A-Za-z]{2})$
from:
The document also explains the logic behind it. However, it has an error (bolded) and also allows lower case, which although legal is not usual, so amended version:
^(GIR 0AA)|((([A-Z][0-9]{1,2})|(([A-Z][A-HJ-Y][0-9]{1,2})|(([A-Z][0-9][A-Z])|([A-Z][A-HJ-Y][0-9]?[A-Z])))) [0-9][A-Z]{2})$
This works with new London postcodes (e.g. W1D 5LH) that previous versions did not.
This is the regex Google serves on their i18napis.appspot.com domain:
GIR[ ]?0AA|((AB|AL|B|BA|BB|BD|BH|BL|BN|BR|BS|BT|BX|CA|CB|CF|CH|CM|CO|CR|CT|CV|CW|DA|DD|DE|DG|DH|DL|DN|DT|DY|E|EC|EH|EN|EX|FK|FY|G|GL|GY|GU|HA|HD|HG|HP|HR|HS|HU|HX|IG|IM|IP|IV|JE|KA|KT|KW|KY|L|LA|LD|LE|LL|LN|LS|LU|M|ME|MK|ML|N|NE|NG|NN|NP|NR|NW|OL|OX|PA|PE|PH|PL|PO|PR|RG|RH|RM|S|SA|SE|SG|SK|SL|SM|SN|SO|SP|SR|SS|ST|SW|SY|TA|TD|TF|TN|TQ|TR|TS|TW|UB|W|WA|WC|WD|WF|WN|WR|WS|WV|YO|ZE)(\d[\dA-Z]?[ ]?\d[ABD-HJLN-UW-Z]{2}))|BFPO[ ]?\d{1,4}
Postcodes are subject to change, and the only true way of validating a postcode is to have the complete list of postcodes and see if it's there.
But regular expressions are useful because they:
- are easy to use and implement
- are short
- are quick to run
- are quite easy to maintain (compared to a full list of postcodes)
- still catch most input errors
But regular expressions tend to be difficult to maintain, especially for someone who didn't come up with it in the first place. So it must be:
- as easy to understand as possible
- relatively future proof
That means that most of the regular expressions in this answer aren't good enough. E.g. I can see that [A-PR-UWYZ][A-HK-Y][0-9][ABEHMNPRV-Y] is going to match a postcode area of the form AA1A — but it's going to be a pain in the neck if and when a new postcode area gets added, because it's difficult to understand which postcode areas it matches.
I also want my regular expression to match the first and second half of the postcode as parenthesised matches.
So I've come up with this:
(GIR(?=\s*0AA)|(?:[BEGLMNSW]|[A-Z]{2})[0-9](?:[0-9]|(?<=N1|E1|SE1|SW1|W1|NW1|EC[0-9]|WC[0-9])[A-HJ-NP-Z])?)\s*([0-9][ABD-HJLNP-UW-Z]{2})
In PCRE format it can be written as follows:
/^
( GIR(?=\s*0AA) # Match the special postcode "GIR 0AA"
|
(?:
[BEGLMNSW] | # There are 8 single-letter postcode areas
[A-Z]{2} # All other postcode areas have two letters
)
[0-9] # There is always at least one number after the postcode area
(?:
[0-9] # And an optional extra number
|
# Only certain postcode areas can have an extra letter after the number
(?<=N1|E1|SE1|SW1|W1|NW1|EC[0-9]|WC[0-9])
[A-HJ-NP-Z] # Possible letters here may change, but [IO] will never be used
)?
)
\s*
([0-9][ABD-HJLNP-UW-Z]{2}) # The last two letters cannot be [CIKMOV]
$/x
For me this is the right balance between validating as much as possible, while at the same time future-proofing and allowing for easy maintenance.
I've been looking for a UK postcode regex for the last day or so and stumbled on this thread. I worked my way through most of the suggestions above and none of them worked for me so I came up with my own regex which, as far as I know, captures all valid UK postcodes as of Jan '13 (according to the latest literature from the Royal Mail).
The regex and some simple postcode checking PHP code is posted below. NOTE:- It allows for lower or uppercase postcodes and the GIR 0AA anomaly but to deal with the, more than likely, presence of a space in the middle of an entered postcode it also makes use of a simple str_replace to remove the space before testing against the regex. Any discrepancies beyond that and the Royal Mail themselves don't even mention them in their literature (see http://www.royalmail.com/sites/default/files/docs/pdf/programmers_guide_edition_7_v5.pdf and start reading from page 17)!
Note: In the Royal Mail's own literature (link above) there is a slight ambiguity surrounding the 3rd and 4th positions and the exceptions in place if these characters are letters. I contacted Royal Mail directly to clear it up and in their own words "A letter in the 4th position of the Outward Code with the format AANA NAA has no exceptions and the 3rd position exceptions apply only to the last letter of the Outward Code with the format ANA NAA." Straight from the horse's mouth!
<?php
$postcoderegex = '/^([g][i][r][0][a][a])$|^((([a-pr-uwyz]{1}([0]|[1-9]\d?))|([a-pr-uwyz]{1}[a-hk-y]{1}([0]|[1-9]\d?))|([a-pr-uwyz]{1}[1-9][a-hjkps-uw]{1})|([a-pr-uwyz]{1}[a-hk-y]{1}[1-9][a-z]{1}))(\d[abd-hjlnp-uw-z]{2})?)$/i';
$postcode2check = str_replace(' ','',$postcode2check);
if (preg_match($postcoderegex, $postcode2check)) {
echo "$postcode2check is a valid postcode<br>";
} else {
echo "$postcode2check is not a valid postcode<br>";
}
?>
I hope it helps anyone else who comes across this thread looking for a solution.
Here's a regex based on the format specified in the documents which are linked to marcj's answer:
/^[A-Z]{1,2}[0-9][0-9A-Z]? ?[0-9][A-Z]{2}$/
The only difference between that and the specs is that the last 2 characters cannot be in [CIKMOV] according to the specs.
Edit: Here's another version which does test for the trailing character limitations.
/^[A-Z]{1,2}[0-9][0-9A-Z]? ?[0-9][A-BD-HJLNP-UW-Z]{2}$/
Some of the regexs above are a little restrictive. Note the genuine postcode: "W1K 7AA" would fail given the rule "Position 3 - AEHMNPRTVXY only used" above as "K" would be disallowed.
the regex:
^(GIR 0AA|[A-PR-UWYZ]([0-9]{1,2}|([A-HK-Y][0-9]|[A-HK-Y][0-9]([0-9]|[ABEHMNPRV-Y]))|[0-9][A-HJKPS-UW])[0-9][ABD-HJLNP-UW-Z]{2})$
Seems a little more accurate, see the Wikipedia article entitled 'Postcodes in the United Kingdom'.
Note that this regex requires uppercase only characters.
The bigger question is whether you are restricting user input to allow only postcodes that actually exist or whether you are simply trying to stop users entering complete rubbish into the form fields. Correctly matching every possible postcode, and future proofing it, is a harder puzzle, and probably not worth it unless you are HMRC.
Basic rules:
^[A-Z]{1,2}[0-9R][0-9A-Z]? [0-9][ABD-HJLNP-UW-Z]{2}$
Postal codes in the U.K. (or postcodes, as they’re called) are composed of five to seven alphanumeric characters separated by a space. The rules covering which characters can appear at particular positions are rather complicated and fraught with exceptions. The regular expression just shown therefore sticks to the basic rules.
Complete rules:
If you need a regex that ticks all the boxes for the postcode rules at the expense of readability, here you go:
^(?:(?:[A-PR-UWYZ][0-9]{1,2}|[A-PR-UWYZ][A-HK-Y][0-9]{1,2}|[A-PR-UWYZ][0-9][A-HJKSTUW]|[A-PR-UWYZ][A-HK-Y][0-9][ABEHMNPRV-Y]) [0-9][ABD-HJLNP-UW-Z]{2}|GIR 0AA)$
Tested against our customers database and seems perfectly accurate.
I use the following regex that I have tested against all valid UK postcodes. It is based on the recommended rules, but condensed as much as reasonable and does not make use of any special language specific regex rules.
([A-PR-UWYZ]([A-HK-Y][0-9]([0-9]|[ABEHMNPRV-Y])?|[0-9]([0-9]|[A-HJKPSTUW])?) ?[0-9][ABD-HJLNP-UW-Z]{2})
It assumes that the postcode has been converted to uppercase and has not leading or trailing characters, but will accept an optional space between the outcode and incode.
The special "GIR0 0AA" postcode is excluded and will not validate as it's not in the official Post Office list of postcodes and as far as I'm aware will not be used as registered address. Adding it should be trivial as a special case if required.
First half of postcode Valid formats
- [A-Z][A-Z][0-9][A-Z]
- [A-Z][A-Z][0-9][0-9]
- [A-Z][0-9][0-9]
- [A-Z][A-Z][0-9]
- [A-Z][A-Z][A-Z]
- [A-Z][0-9][A-Z]
- [A-Z][0-9]
Exceptions
Position 1 - QVX not used
Position 2 - IJZ not used except in GIR 0AA
Position 3 - AEHMNPRTVXY only used
Position 4 - ABEHMNPRVWXY
Second half of postcode
- [0-9][A-Z][A-Z]
Exceptions
Position 2+3 - CIKMOV not used
Remember not all possible codes are used, so this list is a necessary but not sufficent condition for a valid code. It might be easier to just match against a list of all valid codes?
here's how we have been dealing with the UK postcode issue:
^([A-Za-z]{1,2}[0-9]{1,2}[A-Za-z]?[ ]?)([0-9]{1}[A-Za-z]{2})$
Explanation:
- expect 1 or 2 a-z chars, upper or lower fine
- expect 1 or 2 numbers
- expect 0 or 1 a-z char, upper or lower fine
- optional space allowed
- expect 1 number
- expect 2 a-z, upper or lower fine
This gets most formats, we then use the db to validate whether the postcode is actually real, this data is driven by openpoint https://www.ordnancesurvey.co.uk/opendatadownload/products.html
hope this helps
To check a postcode is in a valid format as per the Royal Mail's programmer's guide:
|----------------------------outward code------------------------------| |------inward code-----|
#special↓ α1 α2 AAN AANA AANN AN ANN ANA (α3) N AA
^(GIR 0AA|[A-PR-UWYZ]([A-HK-Y]([0-9][A-Z]?|[1-9][0-9])|[1-9]([0-9]|[A-HJKPSTUW])?) [0-9][ABD-HJLNP-UW-Z]{2})$
All postcodes on doogal.co.uk match, except for those no longer in use.
Adding a ? after the space and using case-insensitive match to answer this question:
'se50eg'.match(/^(GIR 0AA|[A-PR-UWYZ]([A-HK-Y]([0-9][A-Z]?|[1-9][0-9])|[1-9]([0-9]|[A-HJKPSTUW])?) ?[0-9][ABD-HJLNP-UW-Z]{2})$/ig);
Array [ "se50eg" ]
This one allows empty spaces and tabs from both sides in case you don't want to fail validation and then trim it sever side.
^\s*(([Gg][Ii][Rr] 0[Aa]{2})|((([A-Za-z][0-9]{1,2})|(([A-Za-z][A-Ha-hJ-Yj-y][0-9]{1,2})|(([A-Za-z][0-9][A-Za-z])|([A-Za-z][A-Ha-hJ-Yj-y][0-9]?[A-Za-z])))) {0,1}[0-9][A-Za-z]{2})\s*$)
I wanted a simple regex, where it's fine to allow too much, but not to deny a valid postcode. I went with this (the input is a stripped/trimmed string):
/^([a-z0-9]\s*){5,7}$/i
Lengths 5 to 7 (not counting whitespace) means we allow the shortest possible postcodes like "L1 8JQ" as well as the longest ones like "OL14 5ET".
EDIT: Changed the 8 to a 7 so we don't allow 8 character postcodes.
To add to this list a more practical regex that I use that allows the user to enter an empty string is:
^$|^(([gG][iI][rR] {0,}0[aA]{2})|((([a-pr-uwyzA-PR-UWYZ][a-hk-yA-HK-Y]?[0-9][0-9]?)|(([a-pr-uwyzA-PR-UWYZ][0-9][a-hjkstuwA-HJKSTUW])|([a-pr-uwyzA-PR-UWYZ][a-hk-yA-HK-Y][0-9][abehmnprv-yABEHMNPRV-Y]))) {0,1}[0-9][abd-hjlnp-uw-zABD-HJLNP-UW-Z]{2}))$
This regex allows capital and lower case letters with an optional space in between
From a software developers point of view this regex is useful for software where an address may be optional. For example if a user did not want to supply their address details
Have a look at the python code on this page:
http://www.brunningonline.net/simon/blog/archives/001292.html
I've got some postcode parsing to do. The requirement is pretty simple; I have to parse a postcode into an outcode and (optional) incode. The good new is that I don't have to perform any validation - I just have to chop up what I've been provided with in a vaguely intelligent manner. I can't assume much about my import in terms of formatting, i.e. case and embedded spaces. But this isn't the bad news; the bad news is that I have to do it all in RPG. :-(
Nevertheless, I threw a little Python function together to clarify my thinking.
I've used it to process postcodes for me.
We were given a spec:
UK postcodes must be in one of the following forms (with one exception, see below):
§ A9 9AA
§ A99 9AA
§ AA9 9AA
§ AA99 9AA
§ A9A 9AA
§ AA9A 9AA
where A represents an alphabetic character and 9 represents a numeric character.
Additional rules apply to alphabetic characters, as follows:
§ The character in position 1 may not be Q, V or X
§ The character in position 2 may not be I, J or Z
§ The character in position 3 may not be I, L, M, N, O, P, Q, R, V, X, Y or Z
§ The character in position 4 may not be C, D, F, G, I, J, K, L, O, Q, S, T, U or Z
§ The characters in the rightmost two positions may not be C, I, K, M, O or V
The one exception that does not follow these general rules is the postcode "GIR 0AA", which is a special valid postcode.
We came up with this:
/^([A-PR-UWYZ][A-HK-Y0-9](?:[A-HJKS-UW0-9][ABEHMNPRV-Y0-9]?)?\s*[0-9][ABD-HJLNP-UW-Z]{2}|GIR\s*0AA)$/i
But note - this allows any number of spaces in between groups.
I have the regex for UK Postcode validation.
This is working for all type of Postcode either inner or outer
^((([A-PR-UWYZ][0-9])|([A-PR-UWYZ][0-9][0-9])|([A-PR-UWYZ][A-HK-Y][0-9])|([A-PR-UWYZ][A-HK-Y][0-9][0-9])|([A-PR-UWYZ][0-9][A-HJKSTUW])|([A-PR-UWYZ][A-HK-Y][0-9][ABEHMNPRVWXY]))) || ^((GIR)[ ]?(0AA))$|^(([A-PR-UWYZ][0-9])[ ]?([0-9][ABD-HJLNPQ-UW-Z]{0,2}))$|^(([A-PR-UWYZ][0-9][0-9])[ ]?([0-9][ABD-HJLNPQ-UW-Z]{0,2}))$|^(([A-PR-UWYZ][A-HK-Y0-9][0-9])[ ]?([0-9][ABD-HJLNPQ-UW-Z]{0,2}))$|^(([A-PR-UWYZ][A-HK-Y0-9][0-9][0-9])[ ]?([0-9][ABD-HJLNPQ-UW-Z]{0,2}))$|^(([A-PR-UWYZ][0-9][A-HJKS-UW0-9])[ ]?([0-9][ABD-HJLNPQ-UW-Z]{0,2}))$|^(([A-PR-UWYZ][A-HK-Y0-9][0-9][ABEHMNPRVWXY0-9])[ ]?([0-9][ABD-HJLNPQ-UW-Z]{0,2}))$
This is working for all type of format.
Example:
AB10-------------------->ONLY OUTER POSTCODE
A1 1AA------------------>COMBINATION OF (OUTER AND INNER) POSTCODE
WC2A-------------------->OUTER
The accepted answer reflects the rules given by Royal Mail, although there is a typo in the regex. This typo seems to have been in there on the gov.uk site as well (as it is in the XML archive page).
In the format A9A 9AA the rules allow a P character in the third position, whilst the regex disallows this. The correct regex would be:
(GIR 0AA)|((([A-Z-[QVX]][0-9][0-9]?)|(([A-Z-[QVX]][A-Z-[IJZ]][0-9][0-9]?)|(([A-Z-[QVX]][0-9][A-HJKPSTUW])|([A-Z-[QVX]][A-Z-[IJZ]][0-9][ABEHMNPRVWXY])))) [0-9][A-Z-[CIKMOV]]{2})
Shortening this results in the following regex (which uses Perl/Ruby syntax):
(GIR 0AA)|([A-PR-UWYZ](([0-9]([0-9A-HJKPSTUW])?)|([A-HK-Y][0-9]([0-9ABEHMNPRVWXY])?))\s?[0-9][ABD-HJLNP-UW-Z]{2})
It also includes an optional space between the first and second block.
What i have found in nearly all the variations and the regex from the bulk transfer pdf and what is on wikipedia site is this, specifically for the wikipedia regex is, there needs to be a ^ after the first |(vertical bar). I figured this out by testing for AA9A 9AA, because otherwise the format check for A9A 9AA will validate it. For Example checking for EC1D 1BB which should be invalid comes back valid because C1D 1BB is a valid format.
Here is what I've come up with for a good regex:
^([G][I][R] 0[A]{2})|^((([A-Z-[QVX]][0-9]{1,2})|([A-Z-[QVX]][A-HK-Y][0-9]{1,2})|([A-Z-[QVX]][0-9][ABCDEFGHJKPSTUW])|([A-Z-[QVX]][A-HK-Y][0-9][ABEHMNPRVWXY])) [0-9][A-Z-[CIKMOV]]{2})$
I needed a version that would work in SAS with the PRXMATCH and related functions, so I came up with this:
^[A-PR-UWYZ](([A-HK-Y]?\d\d?)|(\d[A-HJKPSTUW])|([A-HK-Y]\d[ABEHMNPRV-Y]))\s?\d[ABD-HJLNP-UW-Z]{2}$
Test cases and notes:
/*
Notes
The letters QVX are not used in the 1st position.
The letters IJZ are not used in the second position.
The only letters to appear in the third position are ABCDEFGHJKPSTUW when the structure starts with A9A.
The only letters to appear in the fourth position are ABEHMNPRVWXY when the structure starts with AA9A.
The final two letters do not use the letters CIKMOV, so as not to resemble digits or each other when hand-written.
*/
/*
Bits and pieces
1st position (any): [A-PR-UWYZ]
2nd position (if letter): [A-HK-Y]
3rd position (A1A format): [A-HJKPSTUW]
4th position (AA1A format): [ABEHMNPRV-Y]
Last 2 positions: [ABD-HJLNP-UW-Z]
*/
data example;
infile cards truncover;
input valid 1. postcode &$10. Notes &$100.;
flag = prxmatch('/^[A-PR-UWYZ](([A-HK-Y]?\d\d?)|(\d[A-HJKPSTUW])|([A-HK-Y]\d[ABEHMNPRV-Y]))\s?\d[ABD-HJLNP-UW-Z]{2}$/',strip(postcode));
cards;
1 EC1A 1BB Special case 1
1 W1A 0AX Special case 2
1 M1 1AE Standard format
1 B33 8TH Standard format
1 CR2 6XH Standard format
1 DN55 1PT Standard format
0 QN55 1PT Bad letter in 1st position
0 DI55 1PT Bad letter in 2nd position
0 W1Z 0AX Bad letter in 3rd position
0 EC1Z 1BB Bad letter in 4th position
0 DN55 1CT Bad letter in 2nd group
0 A11A 1AA Invalid digits in 1st group
0 AA11A 1AA 1st group too long
0 AA11 1AAA 2nd group too long
0 AA11 1AAA 2nd group too long
0 AAA 1AA No digit in 1st group
0 AA 1AA No digit in 1st group
0 A 1AA No digit in 1st group
0 1A 1AA Missing letter in 1st group
0 1 1AA Missing letter in 1st group
0 11 1AA Missing letter in 1st group
0 AA1 1A Missing letter in 2nd group
0 AA1 1 Missing letter in 2nd group
;
run;
Below method will check the post code and provide complete info
const valid_postcode = postcode => {
try {
postcode = postcode.replace(/\s/g, "");
const fromat = postcode
.toUpperCase()
.match(/^([A-Z]{1,2}\d{1,2}[A-Z]?)\s*(\d[A-Z]{2})$/);
const finalValue = `${fromat[1]} ${fromat[2]}`;
const regex = /^([Gg][Ii][Rr] 0[Aa]{2})|((([A-Za-z][0-9]{1,2})|(([A-Za-z][A-Ha-hJ-Yj-y][0-9]{1,2})|(([AZa-z][0-9][A-Za-z])|([A-Za-z][A-Ha-hJ-Yj-y][0-9]?[A-Za-z]))))[0-9][A-Za-z]{2})$/i;
return {
isValid: regex.test(postcode),
formatedPostCode: finalValue,
error: false,
info: 'It is a valid postcode'
};
} catch (error) {
return { error: true , info: 'Invalid post code has been entered!'};
}
};
valid_postcode('GU348RR')
result => {isValid: true, formatedPostCode: "GU34 8RR", error: false, info: "It is a valid postcode"}
valid_postcode('sdasd4746asd')
result => {error: true, info: "Invalid post code has been entered!"}
valid_postcode('787898523')
result => {error: true, info: "Invalid post code has been entered!"}
I stole this from an XML document and it seems to cover all cases without the hard coded GIRO:
%r{[A-Z]{1,2}[0-9R][0-9A-Z]? [0-9][A-Z]{2}}i
(Ruby syntax with ignore case)
