README.md

---
tags:
- name
- lang
- iso-3166
- subdivisions
configs:
- config_name: default
  data_files:
  - split: train
    path: data/train-*
dataset_info:
  features:
  - name: code
    dtype: string
  - name: name
    dtype: string
  - name: name_en
    dtype: string
  - name: name_ru
    dtype: string
  - name: name_zh
    dtype: string
  - name: names_en_alt
    list: string
  - name: names_ru_alt
    list: string
  - name: names_zh_alt
    list: string
  - name: names_other
    list: string
  - name: region
    dtype: string
  - name: parent
    dtype: string
  - name: children
    list: string
  - name: links
    list: string
  - name: note
    dtype: string
  - name: lang
    dtype: string
  splits:
  - name: train
    num_bytes: 2051738
    num_examples: 5046
  download_size: 3823324
  dataset_size: 2051738
---

# ISO 3166-2 Subdivision Codes with Lang

Regional subdivision codes with language selection.

## Fields

- **code** (string): ISO 3166-2 subdivision code (e.g., 'US-CA', 'RU-MOW')
- **name** (string): Primary name in selected language
- **region** (string): Parent ISO 3166-1 alpha-2 region code
- **name_en** (string): English name
- **name_ru** (string): Russian name
- **name_zh** (string): Chinese name
- **lang** (string): Language of primary name field (en, ru, or zh)
  - Determined by parent region's language rule
- **parent** (string): Parent subdivision code (if applicable)
- **children** (list): Child subdivision codes
- **names_en_alt** (list): Alternative English names
- **names_ru_alt** (list): Alternative Russian names
- **names_zh_alt** (list): Alternative Chinese names
- **names_other** (list): Names in other languages
- **links** (list): Reference links
- **note** (string): Additional notes

## Language Rule

Languages are determined by parent region using hardcoded mapping (same as iso_3166-1_alpha-2).

## Usage

```python
from datasets import load_dataset

ds = load_dataset('cterdam/iso_3166-2', split='train')
# Filter by region
ru_subdivs = ds.filter(lambda x: x['region'] == 'RU')
print(ru_subdivs[0])
# {
#   'code': 'RU-MOW',
#   'name': 'Москва',
#   'region': 'RU',
#   'lang': 'ru',
# }
```

## See Also

- `cterdam/iso_3166-1_alpha-2`: Countries/regions with lang
- `cterdam/iata-metro`: IATA metro codes with lang and coordinates


## Invariants

All entries in this dataset maintain the following invariants (verified by `test/test_invariants.py`):

### Name Field
- **Required**: Every entry has a `name` field
- **Constraint**: `name` always equals one of `name_en`, `name_ru`, or `name_zh` (based on `lang`)
- **Example**: If `lang: ru`, then `name == name_ru`

### Lang Field
- **Required**: Every entry has a `lang` field
- **Values**: One of `en`, `ru`, or `zh`
- **Determination**: Hardcoded by region (not inferred from text)
  - **Slavic regions** (RU, UA, BY, KZ, etc.) → `lang: ru`
  - **Sinophone regions** (CN, TW, HK, JP, etc.) → `lang: zh`
  - **All others** → `lang: en`

## Verify Invariants

Clone the dataset and run tests:

\`\`\`bash
git clone https://huggingface.co/datasets/cterdam/iso_3166-2
cd iso_3166-2

# Install dependencies
pip install datasets

# Run invariant tests
pytest test/test_invariants.py -v
\`\`\`

Expected output: All tests pass, verifying dataset integrity.