Python 按日期从其他数据帧的累积数据填充数据帧

我有一个带有患者ID、入院日期和医院名称的数据框。我想创建第二个数据框，按日期统计患者数量

我的数据帧

data = {'Patient_admitted_id':  ['2323423', '234234234','234234234','324234234'],
        'Date': ['2021-01-01', '2021-01-01','2021-01-01', '2021-01-02'],
        'Hospital name' : ['Hospital1',"Hospital2","Hospital1", "Hospital3"]}

df = pd.DataFrame(data, columns=['Patient_admitted_id', 'Date', 'Hospital name' ])

Patient_admitted_id     Date      Hospital name
0   2323423           2021-01-01    Hospital1
1   234234234         2021-01-01    Hospital2
2   234234234         2021-01-01    Hospital1
3   324234234         2021-01-02    Hospital3
...

我正在尝试创建的数据帧

Date                 Cases        
0   2021-01-01        3             
1   2021-01-02        1             
2   2021-01-03        0             
...

---

以不同的计数进行测试

选项1:

   date_count = df.groupby('Date').groups

cases = df.pivot_table(index = ['Date', 'Patient_admitted_id'], aggfunc ='size')

2021-01-01和2021-01-02分别有3例和1例-如您所愿

选项2:

   date_count = df.groupby('Date').groups

cases = df.pivot_table(index = ['Date', 'Patient_admitted_id'], aggfunc ='size')

Priettify和Format

date_count = df.groupby('Date').count()

date_count

您试过使用吗？