一、time与datetime模块：
a、time模块：
1. 时间戳(浮点型)：time.time()--->1558758118.7347946; # 从1970年1月1日00:00:00开始按秒计算的偏移量；
2. 格式化的时间字符串：time.strftime('%Y-%m-%d %X')--->2019-05-25 12:21:58;
%a Locale’s abbreviated weekday name. %A Locale’s full weekday name. %b Locale’s abbreviated month name. %B Locale’s full month name. %c Locale’s appropriate date and time representation. %d Day of the month as a decimal number [01,31]. %H Hour (24-hour clock) as a decimal number [00,23]. %I Hour (12-hour clock) as a decimal number [01,12]. %j Day of the year as a decimal number [001,366]. %m Month as a decimal number [01,12]. %M Minute as a decimal number [00,59]. %p Locale’s equivalent of either AM or PM. (1) %S Second as a decimal number [00,61]. (2) %U Week number of the year (Sunday as the first day of the week) as a decimal number [00,53]. All days in a new year preceding the first Sunday are considered to be in week 0. (3) %w Weekday as a decimal number [0(Sunday),6]. %W Week number of the year (Monday as the first day of the week) as a decimal number [00,53]. All days in a new year preceding the first Monday are considered to be in week 0. (3) %x Locale’s appropriate date representation. %X Locale’s appropriate time representation. %y Year without century as a decimal number [00,99]. %Y Year with century as a decimal number. %z Time zone offset indicating a positive or negative time difference from UTC/GMT of the form +HHMM or -HHMM, where H represents decimal hour digits and M represents decimal minute digits [-23:59, +23:59]. %Z Time zone name (no characters if no time zone exists). %% A literal '%' character.
3. 结构化的时间(struct_time)：struct_time元组共有9个元素共九个元素:(年，月，日，时，分，秒，一周中第几天，一年中第几天，夏令时)
time.localtime()--->time.struct_time(tm_year=2019, tm_mon=5, tm_mday=25, tm_hour=12, tm_min=21, tm_sec=58, tm_wday=5, tm_yday=145, tm_isdst=0);
4. 将一个时间戳转换为UTC时区（0时区）：time.gmtime()--->time.struct_time(tm_year=2019, tm_mon=5, tm_mday=25, tm_hour=4, tm_min=21, tm_sec=58, tm_wday=5, tm_yday=145, tm_isdst=0);
5. 将一个结构化时间转化为时间戳：time.mktime(time.localtime())--->1558763371.0；
6. 将一个结构化时间转化为格式化时间：time.strftime('%Y-%m-%d %X',time.localtime())--->2019-05-25 13:57:13；
7. 将一个格式化时间字符串转化为结构化时间：time.strptime('2019-05-25 13:57:13','%Y-%m-%d %X')--->time.struct_time(tm_year=2019, tm_mon=5, tm_mday=25, tm_hour=13, tm_min=57, tm_sec=13, tm_wday=5, tm_yday=145, tm_isdst=-1)；
8. 将结构时间转换为 周几 几月 几号 时：分：秒 年 ：time.asctime(time.localtime())--->Sat May 25 15:41:13 2019；
9. 将时间戳转换为 周几 几月 几号 时：分：秒 年 ：time.ctime(time.time())--->Sat May 25 15:41:13 2019；
b. datetime模块 （时间加减）
1. 当前时间：datetime.datetime.now()--->2019-05-25 16:00:11.794955；
2. 当前日期：datetime.date.fromtimestamp(time.time())--->2019-05-25；
3. 当前时间+2天：datetime.datetime.now()+datetime.timedelta(2)--->2019-05-27 16:00:11.794955；
4. 当前时间+1小时：datetime.datetime.now()+datetime.timedelta(hours=1)--->2019-05-25 17:00:11.794955；
5. 当前时间：datetime.datetime.now()+datetime.timedelta(minutes=1)--->2019-05-25 16:01:11.794955；
6. 替换时间：datetime.datetime.now().replace(minute=12,hour=12)--->2019-05-25 12:12:11.794955；