Question 1

How do I install the countries gem in Rails?

Accepted Answer

Add 'gem "countries"' to your Gemfile and run bundle install. For global helper access, require 'countries/global', but beware of conflicts with existing Country constants in your app.

Question 2

Countries gem or raw JSON files for country data?

Accepted Answer

The gem is best for Ruby apps needing object-oriented queries and dynamic methods, while the raw JSON/YAML data submodules are suitable for non-Ruby projects or when you want direct control over the data structure.

Question 3

How to get subdivision names in Spanish using the countries gem?

Accepted Answer

Use the subdivision_names_with_codes method with the 'es' locale, e.g., ISO3166::Country['US'].subdivision_names_with_codes('es'), which returns an array of name-code pairs translated to Spanish.

Question 4

Does the countries gem support timezone data?

Accepted Answer

Yes, but it's optional. You must add the tzinfo gem to your Gemfile, and then timezone info becomes accessible via methods like timezones.zone_identifiers on country objects.

Question 5

How can I reduce memory usage with the countries gem locales?

Accepted Answer

Configure locales selectively in an initializer using ISO3166.configure { |c| c.locales = [:en, :fr] } to load only necessary translations, then call ISO3166::Data.reset to apply changes and free memory.

Question 6

What are the breaking changes in countries gem version 5.0?

Accepted Answer

Version 5.0 removed deprecated methods like find_by_name, dropped support for Ruby 2.5 and 2.6, and standardized name attributes to ISO terms. Always check UPGRADE.md before upgrading to avoid surprises.

Countries

What is Countries?

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Frequently Asked Questions