如何在一个数据帧中获得多个聚合？cumsum和count列

import pandas as pd

# 创建示例数据帧
data = {
    'date': ['2023-01-01', '2023-01-02', '2023-01-03', '2023-01-04'],
    'sales': [100, 200, 150, 300],
    'customer_id': [1, 2, 1, 3]
}
df = pd.DataFrame(data)

# 计算累计和（cumsum）和计数（count）
df['cumulative_sales'] = df['sales'].cumsum()
df['sales_count'] = df.groupby('date')['sales'].transform('count')

print(df)

         date  sales  customer_id  cumulative_sales  sales_count
0  2023-01-01     100            1                100           1
1  2023-01-02     200            2                300           1
2  2023-01-03     150            1                450           1
3  2023-01-04     300            3                750           1

df['sales'].fillna(0).cumsum()

df['sales_count'] = df.groupby('date')['sales'].transform('count')