import pandas as pd

provincial = pd.read_parquet("data/provincial_annual/provincial_annual.parquet")
key_cities = pd.read_parquet("data/key_city_annual/key_city_annual.parquet")
national = pd.read_parquet("data/national_structure/national_structure.parquet")

print(provincial.head())
print(key_cities[key_cities["region_name"] == "成都市"].sort_values("stat_year"))
print(national[national["metric_code"] == "resident_total_population"].sort_values("stat_year").tail())