datetime模块

1、当前日期、当前时间

import datetime
a = datetime.date.today()
b = datetime.datetime.today()

2、日期与其他格式转换

#日期转换成字符串
to_str = a.strftime("%Y-%m-%d %H:%M:%S")
#字符串转换日期
detester = '2017-01-01 10:00:00'
date = datetime.datetime.strptime(detester,'%Y-%m-%d %H:%M:%S')
#数字转换日期
from dateutil.parser import parse
a = 20190613
b = str(a)
c = parse(b)
print(c)

3、两个日期加减

d1 = datetime.datetime.strptime('2019-03-05 17:42:00', '%Y-%m-%d %H:%M:%S')
d2 = datetime.datetime.strptime('2019-03-02 17:41:00', '%Y-%m-%d %H:%M:%S')
delta = d1 - d2
#timedelta对象
delta
#返回具体的秒数
delta.total_seconds()

4、n天后的日期

now = datetime.datetime.now()
delta = datetime.timedelta(days=3)
n_days = now + delta
n_days.strftime('%Y-%m-%d %H:%M:%S')

 5、根据日期返回星期

def get_week_day(date):
    week_day_dict = {
    0 : '星期一',
    1 : '星期二',
    2 : '星期三',
    3 : '星期四',
    4 : '星期五',
    5 : '星期六',
    6 : '星期天',
    }
    day = date.weekday()
    return week_day_dict[day]

print(datetime.datetime.now())
print(get_week_day(datetime.datetime.now()))