import time
st = '00:00:10'
et = '00:10:20'
se = "2016-11-21 " + st
ee = "2016-11-21 " + et
i = time.mktime(time.strptime(se, '%Y-%m-%d %H:%M:%S'))
j = time.mktime(time.strptime(ee, '%Y-%m-%d %H:%M:%S'))
print(int(j - i))
# mktime()接收struct_time对象或完整的9个元组，返回用秒数表示时间的浮点数
# strptime()根据指定格式把时间字符串解析为时间元组

from datetime import datetime
x = datetime.strptime(se, '%Y-%m-%d %H:%M:%S')
y = datetime.strptime(ee, '%Y-%m-%d %H:%M:%S')
print((y - x).seconds)