python获取一个月之前日期_python获取当前时间的前一天，前一周，前一个月。

datetime.timedelta的使用来避免跨年跨月的问题

1.[代码][Python]代码

import datetime

d = datetime.datetime.now()

def day_get(d):

oneday = datetime.timedelta(days=1)

day = d - oneday

date_from = datetime.datetime(day.year, day.month, day.day, 0, 0, 0)

date_to = datetime.datetime(day.year, day.month, day.day, 23, 59, 59)

print '---'.join([str(date_from), str(date_to)])

def week_get(d):

dayscount = datetime.timedelta(days=d.isoweekday())

dayto = d - dayscount

sixdays = datetime.timedelta(days=6)

dayfrom = dayto - sixdays

date_from = datetime.datetime(dayfrom.year, dayfrom.month, dayfrom.day, 0, 0, 0)

date_to = datetime.datetime(dayto.year, dayto.month, dayto.day, 23, 59, 59)

print '---'.join([str(date_from), str(date_to)])

def month_get(d):

dayscount = datetime.timedelta(days=d.day)

dayto = d - dayscount

date_from = datetime.datetime(dayto.year, dayto.month, 1, 0, 0, 0)

date_to = datetime.datetime(dayto.year, dayto.month, dayto.day, 23, 59, 59)

print '---'.join([str(date_from), str(date_to)])