python中时间戳，datetime 和时间字符串之间得转换

# datetime时间转为字符串
def Changestr(datetime1):
    str1 = datetime1.strftime('%Y-%m-%d %H:%M:%S')
    return str1

# 字符串时间转为时间戳
def Changetime(str1):
    Unixtime = time.mktime(time.strptime(str1, '%Y-%m-%d %H:%M:%S'))
    return Unixtime

# datetime时间转为时间戳
def Changestamp(dt1):
    Unixtime = time.mktime(time.strptime(dt1.strftime('%Y-%m-%d %H:%M:%S'), '%Y-%m-%d %H:%M:%S'))
    return Unixtime

# 时间戳转为datetime时间
def Changedatetime(timestamp):
    dt = datetime.datetime.fromtimestamp(timestamp)
    return dt

# uinx时间戳转换为本地时间
def Localtime(datetime1):
    Localtime = time.strftime('%Y-%m-%d %H:%M:%S',time.localtime(datetime1))
    return Localtime

# 字符串时间转换函数
def Normaltime(datetime1):
    Normaltime = datetime.datetime.strptime(datetime1,'%Y-%m-%d %H:%M:%S')
    return Normaltime

import time
import datetime
#  首先将时间字符串处理成标准的，即将小数位去掉
time_stamp = "2019-04-10 00:30:10.198" .split('.')[0]

#  将字符串转化为时间戳
h =  time.mktime(time.strptime(time_stamp, "%Y-%m-%d %H:%M:%S"))

#  将时间戳转换为字符串
start_time = time.strftime("%Y-%m-%d %H:%M:%S", time.localtime(h-30))
end_time = time.strftime("%Y-%m-%d %H:%M:%S", time.localtime(h+30))

#  将时间字符串转化为datetime类型
start_date = datetime.datetime.strptime(start_time, "%Y-%m-%d %H:%M:%S")

#  将时间戳转化为datetime类型
t = datetime.datetime.fromtimestamp(h)
print(t,type(t))

print(start_date,type(start_date))