| ▲ | stackskipton 3 days ago |
| Someone who deals with this, reason you type in the Zip Code is its rudimentary checksum to make sure someone put in right information. > There wasn't any easily downloadable file that had every ZIP code though Post Service says what? https://postalpro.usps.com/ZIP_Locale_Detail (Heads up, it's Excel document) |
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| ▲ | BrandoElFollito 2 days ago | parent | next [-] |
| > reason you type in the Zip Code is its rudimentary checksum to make sure someone put in right information. I did not know you had a checksum in US zipcodes (I am French, oir zip codes are for the most part "region number"+"number that may tell about the importance of the city or carry a completely different meaning". 78000 is Versailles, which would make the city the "most important" city of the 78 "region", one of the ones around Paris. 78140 is another city, and 78142 (a mde up number) would be some internal numbering in the city, usually linked to a post office and usually unknown to the everyday Joe. How this gets complicated is fascinating. |
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| ▲ | samtheDamned 15 hours ago | parent [-] | | I believe what the OP you replied to meant was that when entering your address in a form, the zip code allows for verification that the address was all entered correctly. Lets say someone wants to buy a book and they put their address in as 154 Broad Street, Philadelphia PA but they actually live in a neighboring county, when they put in their zip code the system will be able to see that the address was slightly incorrect and can be adjusted to ensure a smoother delivery. I know where I live what "city" you live in can be a complex situation because of unusual classifications of cities compared to the rest of the country so I can see this being a useful system to have. | | |
| ▲ | BrandoElFollito 12 hours ago | parent [-] | | Ah thank you - I get it now. We wouldn't have that problem in France where the cities are clearly separated. The concept of "city" (commune) is the basis for the topography classification of the country since 1789. So when I input an address, a suggestion system will give me several choices with several distinct cities and zips. If I input a zip code, I can get several choices of "places" under one zip. A situation where your address is in the neighbour city should not happen (I put "should" because this is France :)) |
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| ▲ | pseudosavant 3 days ago | parent | prev | next [-] |
| Nice find! Looks like something they recently added. Before I made this project I was looking for exactly something like that and I couldn't find it anywhere. |
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| ▲ | Spooky23 3 days ago | parent | prev [-] |
| The only gotcha with the zip code reverse lookup is that there is a many to one relationship between city and zip. Look at Albany, NY (12201-12209) in the list you posted. There are a few with two cities, and iirc there are at least 3 other acceptable cities for 12203 that aren’t listed in that source. |
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| ▲ | dreamcompiler 3 days ago | parent | next [-] | | My zip code maps to two different cities in two different counties. This causes endless problems with registering my car because the state wants to know what county my car is in and the webpage was programmed with the false assumption "every zip code exists entirely within one county." USPS doesn't much care about counties. They assign postal routes based on geographical convenience, not political borders. | |
| ▲ | stackskipton 3 days ago | parent | prev [-] | | ON systems I work with, we run entire Street, City, State into Zip code lookup and compare with Zip code provided. If it's within postal code, we may present it to be corrected. If it's way off, we say "Umm, something is way off here, please try again." and flag it for fraud check. |
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