python datetime获取几分钟、小时、天之前的时间

import datetime

print ((datetime.datetime.now()-datetime.timedelta(days=1)).strftime("%Y-%m-%d %H:%M"))
print ((datetime.datetime.now()-datetime.timedelta(minutes=1)).strftime("%Y-%m-%d %H:%M"))
print ((datetime.datetime.now()-datetime.timedelta(seconds=1)).strftime("%Y-%m-%d %H:%M"))

　　输出结果

 以下是随机获取15天前的日期和时间实例：

import datetime
import random
d = random.randint(0,15)
date = ((datetime.datetime.now()-datetime.timedelta(days=d)).strftime("%Y-%m-%d %H:%M:%S"))
# print date
day = date[0:11]
# print "day:", day

h = random.randint(0,24)
date = ((datetime.datetime.now()-datetime.timedelta(hours=h)).strftime("%Y-%m-%d %H:%M:%S"))
# print date
hour = date[11:13]
# print "hour: ",hour

m = random.randint(0,15)
date = ((datetime.datetime.now()-datetime.timedelta(minutes=m)).strftime("%Y-%m-%d %H:%M:%S"))
# print date
minue = date[14:16]
# print "minue: ", minue
s = random.randint(0,24)
date = ((datetime.datetime.now()-datetime.timedelta(seconds=s)).strftime("%Y-%m-%d %H:%M:%S"))
# print date
second = date[17:19]
# print "second: ", second

new_time = hour+":"+minue+":"+second
print day,new_time

　输出结果：

　

实例：

#coding:UTF-8

import time
import datetime
import random

def get_time():
    d = random.randint(0,15)
    date = ((datetime.datetime.now()-datetime.timedelta(days=d)).strftime("%Y-%m-%d %H:%M:%S"))
    # print date
    day = date[0:11]
    # print "day:", day

    h = random.randint(0,24)
    date = ((datetime.datetime.now()-datetime.timedelta(hours=h)).strftime("%Y-%m-%d %H:%M:%S"))
    # print date
    hour = date[11:13]
    # print "hour: ",hour

    m = random.randint(0,15)
    date = ((datetime.datetime.now()-datetime.timedelta(minutes=m)).strftime("%Y-%m-%d %H:%M:%S"))
    # print date
    minue = date[14:16]
    # print "minue: ", minue
    s = random.randint(0,24)
    date = ((datetime.datetime.now()-datetime.timedelta(seconds=s)).strftime("%Y-%m-%d %H:%M:%S"))
    # print date
    second = date[17:19]
    # print "second: ", second

    new_time = hour+":"+minue+":"+second
    return day.strip(),new_time.strip()

day,times=get_time()
print day
print times
str_1 = '{"PN":"34VT123","DUID":"XXXX","location":{"coordinates":[-100.35256443,33.4586858]},"SPD":125,"DT":"'
str_2 = 'Z","driverID":"XXXXX","cate":"event","subCate":"OBDII","eventOBDII":{"what":"emergencyBrake","param":2,"GID":123456479}}'
des_str = '2017-06-02T13:15:20'
str_des = str_1 + day + 'T' + times + str_2
print str_des

　输出

> "D:\Python27\python.exe"  "F:\MQTT_testing\data.py"
2017-05-26
02:21:19
{"PN":"34VT123","DUID":"XXXX","location":{"coordinates":[-100.35256443,33.4586858]},"SPD":125,"DT":"2017-05-26T02:21:19Z","driverID":"XXXXX","cate":"event","subCate":"OBDII","eventOBDII":{"what":"emergencyBrake","param":2,"GID":123456479}}