python 时间与字符转换

1.当前时间转字符串
datetime.datetime.strftime(datetime.datetime.now(),"%Y-%m-%d")

2.当前时间减3天，然后转字符串
(datetime.datetime.now()+datetime.timedelta(days=-3)).strftime('%Y-%m-%d %H:%M:%S')

3.根据给定的时间，创建时间范围列表
date_index=pd.date_range('2020-10-30',datetime.datetime.strftime(datetime.datetime.now(),"%Y-%m-%d"))
显示结果：
['2021-02-01T00:00:00.000000000' '2021-02-02T00:00:00.000000000' '2021-02-03T00:00:00.000000000' '2021-02-04T00:00:00.000000000'
'2021-02-05T00:00:00.000000000' '2021-02-06T00:00:00.000000000' '2021-02-07T00:00:00.000000000']

date_list=[pd.Timestamp(x).strftime("%Y-%m-%d") for x in date_index.values]
显示结果:
date_list=['2021-02-01', '2021-02-02', '2021-02-03', '2021-02-04', '2021-02-05', '2021-02-06', '2021-02-07']

4. 取三个月前的日期
yestmonth3 = (datetime.datetime.now() + relativedelta(months=-3)).date()

5.获取日期中的年月日，小时,分钟，秒
datetime.datetime.strptime('2020-01-01 12:01:02', '%Y-%m-%d %H:%M:%S').year
datetime.datetime.strptime('2020-01-01 12:01:02', '%Y-%m-%d %H:%M:%S').month
datetime.datetime.strptime('2020-01-01 12:01:02', '%Y-%m-%d %H:%M:%S').day
datetime.datetime.strptime('2020-01-01 12:01:02', '%Y-%m-%d %H:%M:%S').hour
datetime.datetime.strptime('2020-01-01 12:01:02', '%Y-%m-%d %H:%M:%S').minute
datetime.datetime.strptime('2020-01-01 12:01:02', '%Y-%m-%d %H:%M:%S').second
或者：
date_tuple=datetime.datetime.strptime('2021-02-07 12:01:02', '%Y-%m-%d %H:%M:%S').timetuple()
返回时间元组，按索引取值对应的值

6.日期是星期几，星期一返回值为整数1，星期日返回值为整数7
datetime.datetime.strptime('2021-02-07 12:01:02', '%Y-%m-%d %H:%M:%S').isoweekday()

7.返回当前日期的的星期一和星期天的日期

def get_current_week(days):

if days.find('-')>-1:
days=days.replace('-','')
#传入日期字符串，返回周一到周日日期字符串
monday=datetime.datetime.strptime(days, '%Y%m%d')
sunday = datetime.datetime.strptime(days, '%Y%m%d')

one_day = datetime.timedelta(days=1)
while monday.weekday() != 0:
monday -= one_day
while sunday.weekday() != 6:
sunday += one_day
monday=datetime.datetime.strftime(monday,'%Y%m%d')
sunday = datetime.datetime.strftime(sunday,'%Y%m%d')
# 返回当前的星期一和星期天的日期
return monday+'-'+sunday