python加减日期功能怎么实现

Python中可以使用`datetime`模块来实现日期的加减功能。具体步骤如下：
1. 导入`datetime`模块
```python
from datetime import datetime, timedelta
```
2. 定义一个初始日期`date`
```python
date = datetime(year, month, day)
```
3. 使用`timedelta`来加减日期
```python
# 加一天
new_date = date + timedelta(days=1)
# 减一天
new_date = date - timedelta(days=1)
# 加一周
new_date = date + timedelta(weeks=1)
# 减一周
new_date = date - timedelta(weeks=1)
```
完整示例代码如下：
```python
from datetime import datetime, timedelta
date = datetime(2022, 1, 1)
new_date = date + timedelta(days=1)
print(new_date)
new_date = date - timedelta(days=1)
print(new_date)
new_date = date + timedelta(weeks=1)
print(new_date)
new_date = date - timedelta(weeks=1)
print(new_date)
```
这样就可以实现对日期进行加减的功能了。