some Falsehoods programmers believe via mjt.me.uk

Perhaps you've read posts like Falsehoods Programmers Believe About Names and Falsehoods programmers believe about time. Maybe you've also read Falsehoods programmers believe about geography.

Addressing is a fertile ground for incorrect assumptions, because everyone's used to dealing with addresses and 99% of the time they seem so simple. Below are some incorrect assumptions I've seen made, or made myself, or had reported to me. (If you want to look up an address for a UK postcode or vice-versa to confirm what I'm telling you, try the Royal Mail Postcode Finder)

Counterexample: Royal Opera House, Covent Garden, London, WC2E 9DD, United Kingdom.

Counterexample: - 1A Egmont Road, Middlesbrough, TS4 2HT - 4-5 Bonhill Street, London, EC2A 4BX

Counterexample: 0 Egmont Road, Middlesbrough, TS4 2HT

Guy Chisholm provided this counterexample: Minusone Priory Road, Newbury, RG14 7QS (none of the databases I've checked render this as -1)

Counterexample: Idas Court, 4-6 Princes Road, Hull, HU5 2RD

Counterexample: Flat 1.4, Ziggurat Building, 60-66 Saffron Hill, London, EC1N 8QX, United Kingdom

• The difference between 50 Ammanford Road, Tycroes, Ammanford, SA18 3QJ and 50 Ammanford Road, Llandybie, Ammanford, SA18 3YF is about 4 miles (Google Maps).

Counterexample: Flat 18, Da Vinci House, 44 Saffron Hill, London, EC1N 8FH, United Kingdom

• You also get suite numbers, floor numbers, unit numbers, and organisations with numbers in their names.
• Adrien Piérard contributes an address from Japan with fifteen digits in six separate numbers (five if you count the zip code as a single number). The format is: 980-0804 (zip code), Miyagi-ken (prefecture) Sendai-shi (city) Aoba-ku (ward) Kokubuncho (district) 4-10-20 (sub-district-number block-number lot-number) Sendai (building name) 401 (flat number).

Counterexample: 3 Store, 311-318 High Holborn, London, WC1V 7BN

• Benton Lam offers this address from the Hong Kong Special Administrative Region - it has both a number on its road (14) and in its group of buildings (3): 15/F, Cityplaza 3, 14 TaiKoo Wan Road, Island East, HKSAR

• Tibor Schütz points out building numbers may be skipped - for example, on a street where even-numbered buildings are on one side, odd numbers on the other; multiple buildings sharing the same number (such as where a new house has been built) and buildings with more than one number.

Cyrille Chépélov and Sami Lehtinen tell me in Antibes, France and rural Finland some buildings are numbered based on the distance from the start of the road - such as Longroad 65 for the building 750m from the start of longroad.

• Cyrille Chépélov points out that in places, Boulevard Théophile Sueur, Montreuil, Seine-Saint-Denis, France has evens-only on both sides. The two sides are also in different cities and Départements.

• Ben Tilly reports on Ten Post Office Sq, Boston MA 02109 USA - which is not, reportedly, the same as 10 Post Office Sq, Boston MA 02109 USA.

• Shaun Crampton reports living at 101 Alma St, Apartment 001, Palo Alto - where apartments 1 and 001 were on different floors.

• Douglas Perreault reports he lived in a block within a condo association; it was a large association, with blocks A through Z then Alpha, Beta, Gamma, Delta, and Theta. Mail and deliveries were often misrouted from block Alpha to block A and vice-versa. His address at the time was: 14100 N 46th St., Alpha 39, Tampa, FL 33613

• 8 Seven Gardens Burgh, WOODBRIDGE, IP13 6SU (pointed out by Raphael Mankin)

• Jan Jongboom reports streets can be numbered in the Netherlands - for example, Plein 1944 in Nijmegen.

• Another from Jan Jongboom: Gondel 2695, Lelystad, means area Gondel, street 26, number 95

• They don't always - for example: Piccadilly, London, W1J 9PN

• A street name can be entirely descriptors: 17 Hill Street, London, W1J 5LJ or Avenue Road, Toronto, Ontario.

• French addresses use prefix descriptors like 'rue', 'avenue', 'place' and 'allee'.

• Or the middle, like 3 Bishops Square Business Park, Hatfield, AL10 9NA

• Actually there's a town called Street in Somerset, UK.

• Dan, Fred Kroon, David Underwood and Daniel Dickison submitted examples of fractional street numbers like 43rd ½ St, Pittsburgh, PA, and of fractional building numbers. These can be written in unicode (43rd ½ St), as a fraction with a slash (43 1/2) or as a decimal (43.5)

Gene Wirchenko reports a fractional building number: 1313 1/2 Railroad Ave Bellingham WA 98225-4729

Here's a map of the following addresses:

1. High Street, London, W3 6LJ
2. High Street, London, W5 5DB
3. High Street, London, N8 7PB
4. High Street, London, SE25 6EP
5. High Street, London, E13 0AJ
6. High Street, London, E17 7LD
7. High Street, London, NW10 4LX
8. Islington High Street, London, N1 9TR
9. Shoreditch High Street, London, E1 6PG
10. Camden High Street, London, NW1 0JH
11. Kensington High Street, London, W14 8NL
12. Lewisham High Street, London, SE13 6AD
13. High Street Wimbledon, London, SW19 5DX
14. High Street Wanstead, London, E11 2AJ
15. High Street Colliers Wood, London, SW19 2AE
16. High Street North, London, E6 2HJ

• Julian Fleischer provides an example from Bocholt in Germany showing several roads in close proximity all called Up de Welle.

• Kirk Kerekes spent several years using an address of the form “2 mi N then 3 mi W of Jennings, OK 74038” which regularly got successful deliveries. Mike Riley used to mail the Very Large Array radio telescope at “50 miles (80 km) West of Socorro, New Mexico, USA”
• Sam pointed me to Menomonee Falls where houses are addressed using Milwaukee County's grid system instead of house numbers - giving addresses like N88 W16541 Foobar St.
• Andy Monat sent the following address example, from a semester abroad program at Tulane University : CIAPA, 50 meters north of the Hypermas/Walmart of Curridabat, San Jose, Costa Rica. Adrien Piérard and Luke Allardyce point out street names are seldom used in Japan - instead, districts and blocks and lot numbers are used (more info on the Wikipedia entry for the Japanese addressing system). A 2002 World Press Review report gave this sample address: From where the Chinese restaurant used to be, two blocks down, half a block toward the lake, next door to the house where the yellow car is parked, Managua, Nicaragua. Shaun Crampton sent an article with more details and examples of the Nicaraguan system. Stig Brautaset pointed out a BBC article about post in Kabul gives this example: “Hamid Jaan, behind Darul-Aman palace”. Nathan Fellman reports similar addressing is used in Nicaragua and Costa Rica.
• Paul Puschmann and Tibor Schütz pointed out the city of Mannheim in Germany is sometimes called Quadratestadt (City of Squares) as the city centre is arranged in a grid, with blocks assigned a letter (along the north-south axis) and a number (along the east-west axis) then buildings numbered by block number. So an example address at numbers 6 to 13 on block R 5 would be: Institut für Deutsche Sprache, R 5, 6-13, D-68161 Mannheim

Leoni Lubbinge gives an example of a South African address: Part 84, Strydfontein 306 JR, Pretoria which means the 84th plot of the farm Strydfontein 306 JR.

• Plenty of roads like driveways, onramps and the aisles of carparks don't have names. Some roads in Japan also don't have names, as the prevalent addressing system works on districts, subdistricts, blocks, lots and lot numbers.

Peter Kenway points out in America some homes are addressed as Rural Routes, where numbers are allocated to boxes on a route covering multiple roads. For example: Box 1234, R.R. 1, Winthrop, ME 04364.

• Many different roads, from Goswell Road in London to Regent Road in Edinburgh, make up the 410 mile A1. And while there may only be one “1 Goswell Road” and only one “1 Regent Road” there are multiple buildings numbered 1 on the road designated A1.

Roads may also be named in multiple languages. For example, in Ireland roads may be named in both English and Irish

• The Royal Mail have what they call a 'dependent street' - for example: 6 Elm Avenue, Runcorn Road, Birmingham, B12 8QX, United Kingdom (Runcorn Road is the street, Elm Avenue is the stubby 'dependent street' and isn't unique within the city. Google Maps )

Another counterexample: Rogue Hair, 1 Hopton Parade, Streatham High Road, London, SW16 6EP (Streatham High Road is the street. Hopton Parade is a little row of shops on the road - Google Maps )

• The Royal Mail will deliver to certain premises by name, such as farms and cottages. Example: Oakland, Fairseat, Sevenoaks, TN15 7LT, United Kingdom (Fairseat is the town - this is actually on Vigo Road. Google Maps )

Counterexample: Any address in the United Kingdom.

• Large recipients of mail are sometimes addressed by organisation alone - for example: Electoral Reform Society Ltd, London, N1 1RS, United Kingdom

• Iain Parris and Naath both pointed out that, while many websites ask users for a county, not all countries use them in addressing. For example, the Royal Mail stopped using postal counties in 1996.
• Yves Daoust reports that in Belgium an address only requires a street, postcode and city; example: Boulevard Frère Orban, 27, 4000 Liège. Erik Engheim reports that in Norway Oslo is a By (city), Tettsted (urban area), Kommune (municipality) and Fylke (county) but it usually only appears once in a written address.

• jzwinck points out Singapore is a city-state, leading to addresses like Singapore, Singapore - or even Singapore, Singapore, Singapore if you demand a city, county and country.

• Sure you can - for example the UK has three towns called Newport.
• Jan Jongboom reports from the Netherlands, where there are two cities called Eursinge - in the same province!

• 10 High Street, Newport, PO30 1SS
• 10 High Street, Newport, NP20 1FQ
• 10 High Street, Newport, TF10 7AN

• Richard Fletcher, Lee Hosty, Paul O'Nolan, Simon Diab, Tony Finn, Donal Maccarthy, mark lynch and Donovan all pointed out countries like the Republic of Ireland have addresses without postcodes, or only have postcodes in certain parts of the country. Danny Angus points out this is also the case in Hong Kong.
• Jessica Enders points out the post-paid address of the AEC: Australian Electoral Commission, Reply Paid 9867, your capital city

• Most users will, of course, but I've seen incorrect postcodes on corporate letterheads! Misreading handwritten postcodes seems like a common one.

• Although zip codes in the US usually cover very large areas, Anthony Elizondo points out some buildings have their own zip codes - like the Empire State Building (10118)

In the UK, alphanumeric postcodes are typically much more precise than US zip codes.

• Graham Lee points out DVLA Swansea (that's the whole address), where different departments are identified by postcode: V5Cs are processed at SA99 1BA, driving licences at SA99 1AB and so on.

Malcolm Gilbert points out this example, with five postcodes for five departments:

1. London Borough of Enfield, Civic Centre, Silver Street, ENFIELD, EN1 3ES
2. Returning Officer, London Borough of Enfield, Civic Centre, Silver Street, ENFIELD, EN1 9SA
3. Edmonton, London Borough of Enfield, Civic Centre, Silver Street, ENFIELD, EN1 9SB
4. Enfield North, London Borough of Enfield, Civic Centre, Silver Street, ENFIELD, EN1 9SD
5. Enfield Southgate, London Borough of Enfield, Civic Centre, Silver Street, ENFIELD, EN1 3ZW
6. But the Enfield council website contact page lists their postcode as EN1 3XY - which the Royal Mail think is a PO Box at the sorting office.

• Mostly this is reasonable in the UK, but there are certain exceptions. For example CV4 7AL is the postcode of the University of Warwick - one postcode for 6,000 students living on campus, and academics/administrators working on campus.
• Also, if your customers get things delivered to them when they're on holiday, lots of customers may have the same holiday parks on their accounts.

Some addresses correspond to 'flexible office spaces' and organisations that offer PO Boxes that sound like fancy offices. The Royal Mail lists more than 90 organisations operating out of Tower 42, 25 Old Broad Street, London, EC2N 1HQ. Holiday parks and cottages may also appear on many customers' accounts.

• Victor Nicollet contributes the example of French postcode 75015, representing the XVth arrondissement of Paris, which covers over 230,000 people.

• Mike Cohen reports zip code 33334 covers 3 cities: Oakland Park, Wilton Manors, and Fort Lauderdale, all in Florida.

• Some Brazilian zip codes do according to speeder, as do Israeli postcodes for army units. Jessica Enders and Frank Malcolm pointed out postcodes in the Northern Territory of Australia start with 08; for example the postcode for the city Darwin is 0800. Morsillo Lindsay, Thomas Norris and Jerry B. Altzman point out American addresses in the north east have zip codes starting with zero, for example Ten Post Office Sq, Boston MA 02109, USA; and some zip codes start with two zeros. Mikael Vejdemo-Johansson reports the zip code of Jena in Germany is 07737.
• Antti Vikman and Johan Myréen tell me all postcodes in Helsinki, the capital of Finland, all start with two zeroes. Some special codes even start with four zeroes (00002 HELSINKI). Andrew Jones reports the initial digits of French postcodes are the départements*, and may use a leading zero. Post addressed to 06130 Grasse is correctly delivered to the town in district 06, Alpes Maritimes - but post addressed to 6130 Grasse is first routed to department 61, Orne. klez reports Italian Codice di Avviamento Postale (CAP) numbers can have a leading zero.

1. Except Corsica - Cyrille Chépélov reports it's split into départements 2A and 2B, but the Post Office kept the former single-number 20 (Ajaccio, 20000; Bastia, 20200)

• Not when organisation and department names can be included in addresses! For example: Department For Environment Food & Rural Affairs (D E F R A), State Veterinary Service, Animal Health Office, Hadrian House, Wavell Drive, Rosehill Industrial Estate, Carlisle, CA1 2TB, United Kingdom
• Another example: The Gynaecology Cancer Research Unit, Department of Obstetrics & Gynaecology, St. Bartholomews & The Royal School of Medicine & Dentistry, Charterhouse Square, London, EC1M 6GR, United Kingdom

• Susanne Schmidt provides the longest street name in Germany: Bischöflich-Geistlicher-Rat-Josef-Zinnbauer-Straße in 84130 Dingolfing, Bavaria

Graham Rhind suggests this 89-character street name in Bihac, Bosnia: Aleja Alije Izetbegovića Prvig Predsjednika Predsjedništva Republika Bosna i Hercegovina

• You'll need 8 lines and country to deliver to: GB Technical Services, Unit W7a, Warwick House, 18 Forge Lane, Minworth Industrial Park, Minworth, Sutton Coldfield, B76 1AH, United Kingdom

=== Addresses don't contain commas** (so I can replace newlines with commas then commas with newlines and get back to where I was)

Addresses can contain organisation names, and organisation names can contain commas. For example: Society of College, National & University Libraries, 102 Euston Street, London, NW1 2HA

• St. Judes & St. Pauls C of E (Va) Primary School, 10 Kingsbury Road, London, N1 4AZ
• 1 Acre View, Bo'ness, EH51 9RQ
• 1 Highview Terrace, Westward Ho!, Bideford, EX39 1AQ (exclamation mark is omitted in some databases)
• Flat 1.4, Ziggurat Building, 60-66 Saffron Hill, London, EC1N 8QX, United Kingdom
• Kirkland, Lane, Mathias & Perry, North Muskham Prebend Church Street, Southwell, NG25 0HQ
• Mark Wallace tells us The Hague in the Netherlands is has multiple official names, one of which is 's-Gravenhage (not a plural, literally a city name starting apostrophe s and with a hyphen)
• Signposts for Station Road East, Grantham, NG31 6HX render it as STATION ROAD (EAST).
• More generally, addresses can contain organisation names, and organisations can have names like Yahoo! with an exclamation mark. Legislation on company sets out the allowable characters for the UK and it permits company names including ! LTD (company 08209948); @ LTD (company 08209882); $ LTD (company 08209885) and % LTD (company 04487680) as well as a variety of other names I don't have examples for as the companies house website won't let me search for them.

• Simon Westcott points out databases are only released periodically, so it's not unusual for new buildings to be omitted.

• Royal Mail and Ordnance Survey data can contain demolished buildings, and buildings currently under construction. The Royal Mail even have a database product called Not Yet Built. Temporary postcodes can even be assigned to building sites!

• Christopher Allen points out that people in new blocks of flats and houseboats in boatyards sometimes need to prefix their official address with a boat name or flat number.

• XaspR8d must have been exasperated by the fact his road is variously known as “S Hwy X”, “Highway X” and “South County Rd X” - and related a story of being unable to buy a product as the only addresses that passed a vendor's address validation wouldn't pass his bank's address validation and vice-versa.
• Jon Peterson lives in an apartment community that is divided into Quail Ridge Cir, Quail Ridge East Lane and Quail Ridge West Lane. Only the USPS and the city electric utility seem to recognize the “Lane”. Everyone else requires it be shortened to “Quail Rdg E” (or W) and reportedly when UPS turns a package over to the USPS it gets returned as undeliverable-no such address.
• Susannah Fleming lived on the road the Royal Mail call Top O'The Lane, Brindle, Chorley, PR6 8PA. She reports representations in different databases include:

1. Top o' th' Lane
2. Top o'th' Lane
3. Top oth Lane
4. Top o' the Lane
5. Top of the Lane
6. Workhouse Lane (a historical name of the road)
7. Denham Lane (name of the road continuation)

• A developer just a few seats from me recently brought a house boat with the intention of using it as her primary residence. Needless to say, boats can move - including between towns and even countries!
• fr0sty points out the State of Illinois catch-all approach to addresses: “IF YOU HAVE NO STREET ADDRESS, below describe your home: list the name of subdivision; cross streets; roads; landmarks; mileage and/or neighbors' names.”

Sharon Freas has dealt with systems supporting “Snowbird” clients, who alternate between addresses with the changing seasons.

• Addresses can move between counties and administrative districts. For example, I used to live in the county Gwent, but that no longer exists. Addresses may also be assigned new postcodes.
• Susanne Schmidt points out cities, streets and entire countries were renamed in eastern europe - for example, when Lenin fell out of favour as a street name. Addresses can be in disputed territories, or even war zones.
• Douglas Perreault reports owning a condo that changed address three times; first it was 14100 N 46th St., Alpha 39, Lutz, FL 33549; then a new post office was built and it became 14100 N 46th St., Alpha 39, Tampa, FL 33612; then the ZIP Code changed giving 14100 N 46th St., Alpha 39, Tampa, FL 33613; then the condo association changed to a less error-prone block naming scheme, giving 14410 Hanging Moss Circle, #101, Tampa, FL 33613.

• As you can learn from wikipedia's page on postal counties, even when the Royal Mail used postal counties, they didn't always line up with administrative counties. And of course administrative regions come and go with changes to local government structures - for example, the county I was born in in no longer exists.

• Peter Bailey points out several countries have special military mail to deal with the complexities of delivering to soldiers deployed to other countries, ships at sea and similar; and their addresses don't always follow conventional address formats. For example, the address BFPO, BF1 4FB is the address of the navy vessel HMS Example.

Ed Schiebel reports the postcodes allocated to Israeli army units roam around with the units.

• Addresses such as PO boxes are often only as precise as the recipient's city or sorting office. Jessica Enders tells me the Australian post service Reply Paid addresses (no stamp needed); PO Boxes (Post Office Boxes); GPO Boxes (General Post Office Boxes, in the middle of capital cities only); locked bags; private bags; parcel lockers; parcel collect; “Care of Post Office”; CMA (Community Mail Agent); CPA (Community Postal Agent); CMB (Community Mail Bag) and Mail Service (MS)!
• Tibor Schütz points out many post offices have novelty handling of mail to Santa Claus, even going as far as to allocate special postcodes. For example, in Germany: Santa Claus Nordpolen, Julemandes Postkontor, DK-3900 Nuuk; in Canada: Santa Claus, North Pole, H0H 0H0; in the UK: Father Christmas, Santa's Grotto, Reindeerland, XM4 5HQ

• Matthieu Valleton got in touch to point out his address on Kerguelen Island (Google Map), a French territory in the Indian Ocean, his address was District de Kerguelen (island), Terres Australes et Antarctiques Françaises (territory), via la Réunion (indicates where the mail should be routed through), France (country)

• Monty points out that uncommon political hierarchies can lead to uncommon postal addresses. For example, the entire of the Falkland Islands shares postal code FIQQ 1ZZ. On the other hand, the British Virgin Islands have their own postal code system.

• David Kuder pointed me to a 1990 article: Risks Digest correspondent Tim Kay had problems getting mail sent to his university campus pigeon hole: Timothy L. Kay, Box 256-80, Pasadena, CA 91125. Reportedly automatic systems changed his zip code to 91102. David Kuder identified this was because all Pasadena PO Boxes were in box 91102.

• Alastair Houghton reminds us the Greek tax office's address is Χανδρή 1 & Θεσσαλονίκης, Τ.Κ. 18346, Αθήνα
• Wikipedia has a photo of a parcel where a Russian/Cyrillic address was displayed on a computer with the wrong character encoding, and transcribed from that. Reportedly a russian postal worker was able to reverse the mapping and deliver the parcel.

@shyhoof wrote an poem about an address label with ó converted, via latin1 and two rounds of HTML entities, into ó

• Alastair Houghton points out addresses may be written in the character set of the source country.

• International mail may specify the country (and possibly other details) in both the source and destination countries' character sets, so it can be read by postal workers on both ends.

• Alastair Houghton provided this example of a Japanese address: 〒100-8994 (zip code), 東京都 (Tokyo-to, i.e. Tokyo prefecture or state) 中央区 (Chuo-ku, i.e. Chuo Ward) 八重洲一丁目 (Yaesu 1-chome, i.e. Yaesu district 1st subdistrict) 5番3号 (block 5 lot 3), 東京中央郵便局 (Tokyo Central Post Office). Thanks to Norman Diamond for telling me which parts of the address are which!

• Erik Engheim and Jan Jongboom report in Norway and the Netherlands the building number (within street) comes after the street name, but before the town name.
• Douglas Perreault reports units within American condo associations may be written below the street name. For example: 14100 (position of condo association on street) N 46th St. (street name), Alpha (block within condo association) 39 (unit within block), Lutz (city), FL (state) 33549 (zip). Likewise, when mailing an individual at a company some people put the person's name after the company name, but before the street name.

• György Farkas tells me Hungarian addresses can be written in different orders depending on how many lines are available. If you write the address on one line, it's expressed from less specific to more specific:
• {zip} {town}, {street} {buildingNr}.
• If there are more lines available, the address starts with the street, and if the country is specified, it comes after the town name:
  
  • {street} {buildingNr}.
    
  • {zip} {town}, {country}
  • And if there are no set number of lines, like on an envelope, it's a bit different again:
  • {street} {buildingNr}.
    
  • {town}
    
  • {zip}
    
  • {country}
• Gene Wirchenko tells me in some parts of Canada, suite 123 in building 456 on TheStreet would be written: 123 456 TheStreet whereas in other parts the common formatting is 456 TheStreet #123

• In some countries this is reversed - such as in the Netherlands. For example, Plein 1944 85 D (where Plein 1944 identifies the street, 85 the building and D the flat/apartment).

Sami Lehtinen provides this example from Finland: Kornetintie 6 A II krs (Kornetintie is the street name, 6 the building number, A the staircase, II krs indicates the second floor.

• Toni Cornelissen points out addresses in the The Netherlands, such as: Vroomstraat 1a Rood, 2021HL Haarlem where Vroomstaat is the street, 1a is the building number, and Rood (literally translated as Red) indicates the upper part of the building.

• Buildings like farms and country houses can be at the end of a private road or driveway several hundred meters long.

• Lots of examples of this. For example: The National Museum of Computing, Bletchley Park, Sherwood Drive, Bletchley, Milton Keynes, MK3 6EB. 70m from Roche Gardens, 346m from Sherwood Drive, but only accessible by entering Bletchley Park from Sherwood Drive.

• It's not just Middlesex and Scunthorpe you have to check for; Gary Gale has compiled a map of rude-sounding place names.

• John Dye reports that many doctors' offices, dentists and so on are unable to mail both of a child's divorced parents.

• Tibor Schütz points out people often have a different home and work address.