CPI计算简单价格指数

def solve():
    import pandas as pd
    import matplotlib.pyplot as plt
    url = 'https://data.zuihe.com/cpi_us_2000_2024.csv'
    df = pd.read_csv(url)
    df['date'] = pd.to_datetime(df[['year','month']].assign(day=1))
    df = df.sort_values('date')
    base = df[(df['year']==2000)&(df['month']==12)]['cpi_u'].values[0]
    for y,m in [(2010,12),(2020,12)]:
        cpi = df[(df['year']==y)&(df['month']==m)]['cpi_u'].values[0]
        idx = round(cpi/base*100, 2)
        print(f'{y}年12月价格指数={idx}')
    plt.plot(df['date'], df['cpi_u'], color='steelblue')
    plt.xlabel('年份'); plt.ylabel('CPI'); plt.title('美国CPI时间序列(2000-2024)')
    plt.tight_layout(); plt.show()