能否通过pgeocode以国家名称或邮政编码获取国家代码？

Great question! Let's walk through how pgeocode works and what's possible here:

Core Limitation of pgeocode's Initialization #

First, it's important to note that pgeocode requires a 2-letter ISO country code (like 'fr' for France) to initialize the Nominatim instance. This is because the library loads localized postal code datasets per country under the hood—there's no built-in support for using full country names (e.g., "France") directly in the initialization step.

Using Postal Codes to Automatically Detect Country #

Unfortunately, pgeocode doesn't support auto-detecting the country from a standalone postal code either. Postal code formats vary wildly across countries (some are numeric, some alphanumeric, some have different lengths), so the library can't reliably map a single postal code to its corresponding country without prior context.

Workarounds to Achieve Your Goal #

If you need to use country names or postal codes to get the right pgeocode instance, here are two practical workarounds:

1. Map country names to ISO codes manually
   Create a simple dictionary to translate full country names to their 2-letter codes, then use that to initialize Nominatim:

   import pgeocode
   
   country_mapping = {
       "France": "fr",
       "Germany": "de",
       "United States": "us",
       # Add more countries as needed
   }
   
   # Initialize using a country name
   target_country = "France"
   nomi = pgeocode.Nominatim(country_mapping[target_country])
   print(nomi.query_postal_code("75013"))
   

2. Use a third-party tool to get country code from a postal code
   If you only have a postal code, use a general-purpose geocoding tool to first look up the country associated with the postal code, then use that country code to initialize pgeocode.

Recap of Your Example #

Your original example is the correct, intended usage of pgeocode:

import pgeocode
nomi = pgeocode.Nominatim('fr')
nomi.query_postal_code("75013")

This works because you've explicitly told pgeocode to use France's postal code dataset before querying.

内容的提问来源于stack exchange，提问作者fadingbeat