不同卧室数量房价（分组比较）

def solve():
    import pandas as pd
    import matplotlib.pyplot as plt
    import numpy as np
    
    url = 'https://liangdaima.com/static/data/wooldridge/hprice1.csv'
    df = pd.read_csv(url)
    
    bdrm_means = df.groupby('bdrms')['price'].agg(['mean', 'count'])
    plt.figure(figsize=(10,6))
    plt.bar(bdrm_means.index, bdrm_means['mean'], color='orange', alpha=0.7)
    for i, (idx, row) in enumerate(bdrm_means.iterrows()):
        plt.text(idx, row['mean'] + 5, f'n={int(row["count"])}', ha='center', fontsize=9)
    plt.title('不同卧室数量平均房价', fontsize=14)
    plt.xlabel('卧室数量', fontsize=12)
    plt.ylabel('平均房价（千美元）', fontsize=12)
    plt.grid(axis='y', alpha=0.3)
    plt.tight_layout()
    plt.show()
    return "可视化代码执行完成"