python - 将一年与数据值分开；照顾闰年

Question

这应该很简单，但我无法得到正确的语法。所以，我有一个参数字典如下 -

paramDict = {
StartPostingDateFilter": {
        "msgPrompt": "Start date",        
        "dataType": "datetime",
        "tableField": [{"table":"TableName",
                        "field":"ColumnName"}],
        "value": ["2006-01-01"]
                         } 
             }

StartPostingDateFilter = paramDict['StartPriorDateFilter']['value'][0]

现在，我想从“StartPriorDateFilter”用户提供的日期值中减去一年。如果是闰年，我该如何处理？我想实现以下目标 -

If, StartPostingDateFilter = '2006-01-01'
Then create new variable, NewStartPostingDateFilter = '2005-01-01' 

谢谢。

Answer 1

您可以使用 dateutil:

from dateutil.relativedelta import  relativedelta
from dateutil import parser
d = parser.parse(StartPostingDateFilter)
print((d - relativedelta(years=1)).date())
2005-01-01

您还可以使用日期时间并替换捕获 feb 29th 返回年份 - 1 和 feb 28th(如果是):

d = datetime.strptime(StartPostingDateFilter, "%Y-%m-%d")

sub = d.replace(year=d.year - 1) if (d.month != 2 and d.day) != 29 else datetime(d.year-1, 2, 28)