What is the difference and usage between time and datetime in python

1. Two ways to represent time in Python:

• Timestamp: offset in seconds relative to 1970.1.1 00:00:00, unique

• Time tuple struct_time: 9 elements in total> tm_year: year 1-12> tm_mon: month 1-12> tm_mday: day 1-31> tm_hour: hour 0-23> tm_min: minutes 0-59> tm_sec: seconds 0-59> tm_wday: week 0-6 (0 means Sunday)> tm_day: day of the year 1-366> tm_isdst: whether it is daylight saving, the default is - 1

##2. time

 1. time.time() #当前时间戳, 没参数,唯一值
 2. time.sleep(secs) #暂停几秒
 3. time.gmtime(secs)  #无参得到当前格林尼治时间,有时间戳参数就转为格林尼治结构时间
 4. time.localtime(secs)  #无参得到local结构化时间, 有时间戳参数就转为local结构化时间
           print(time.localtime())  # time.struct_time(tm_year=2022, tm_mon=10, tm_mday=20, tm_hour=11, tm_min=20, tm_sec=44, tm_wday=3, tm_yday=293, tm_isdst=0)
           print(time.localtime(13912345678))  # time.struct_time(tm_year=2410, tm_mon=11, tm_mday=12, tm_hour=20, tm_min=27, tm_sec=58, tm_wday=4, tm_yday=316, tm_isdst=0)
 5. time.strftime(format, t) #将结构化时间转化为自定义的格式化时间 
           print(time.strftime('%Y-%m-%d %H:%M:%S', time.localtime()))  #北京时间
           print(time.strftime('%Y-%m-%d %H:%M:%S', time.localtime(time.time()+60*60)))  #东京时间
 6. time.strptime(string, format) # 将自定义时间(字符串)转化为结构时间
           print(time.strptime("2023-1-11 1:2:3", "%Y-%m-%d %H:%M:%S")) # 将日常格式化时间转为结构化时间
           print(time.strptime("2023-1-11", "%Y-%m-%d")) # 将日常格式化时间转为结构化时间
 7. time.ctime(secs)  # 将一个时间戳转变为一个结构化时间
           print(time.ctime(123))  # Thu Jan  1 08:02:03 1970
           print(time.ctime(time.time() + 60 * 60))  # Thu Oct 20 11:28:32 2023
 8. time.mktime(t) # 将所给结构化时间转化为时间戳
           print(time.mktime(time.localtime(time.time())))  # 1666233100.0
           print(time.time())  # 1666233100.5075898  # 两行的效果是一样的
           # 求一个指定时间的时间戳
           print(time.mktime(time.strptime('2023-2-3', '%Y-%m-%d'))) # 1580659200.0

3. datetime

datetime is much more advanced than time. It can be understood that datetime is encapsulated based on time. Provides more practical functions, mainly including the following categories:

• timedelta: mainly used to calculate time span

• time: only focuses on Time

• date: only focus on date

• datetime: both time and date

are in In actual use, the most commonly used ones are datetime.datetime and datetime.timedelta. The actual use of the other two datetime.date and datetime.time is not much different from datetime.datetime.

1.datetime.datetime

datetime.datetime will mainly have the following attributes and common methods after instantiation:

time_now = datatime.datetime.now()  #实例化

datetime.year
datetime.month
datetime.day
datetime.hour
datetime.minute
datetime.second
datetime.microsecond
datetime.tzinfo()：时区
datetime.date()：返回date对象
datetime.time()：返回time对象
datetime.replace(name=value)
datetime.timetuple()：返回time.struct_time 对象
datetime.strftime(format)：按照format进行格式化输出
#除了实例本身具有的方法,类本身也提供了很多好用的方法：

datetime.strptime(date_string,format)： 给定时间格式解析字符串
datetime.now([tz])：当前时间默认 localtime
datetime.today()：当前时间

2.datetime.timedelta

date.timedelta(3), go forward 3 days

date.timedelta(-3), go back 3 days
date.timedelta(hour = 3), go forward 3 hours
date.timedelta(minutes = 3) ,advance 3 minutes

import time
import datetime

dt = datetime.datetime.now()

print(dt.timestamp())
print(dt.year)
print(dt.month)
print(dt.day)
print(dt.hour)
print(dt.minute)
print(dt.second)
print(dt.microsecond)
print(dt.tzinfo)
print(dt.time())
print(dt.date())
print(dt.strftime("%Y-%m-%d %H:%M:%S"))  # 2023-1-31 13:42:16
print(datetime.datetime.strptime('2023-1-20 1:1:1', "%Y-%m-%d %H:%M:%S"))

delta = datetime.timedelta(11)

print(dt + delta)
print((dt + delta).strftime("%Y-%m-%d %H:%M:%S"))
print((dt - delta).strftime("%Y-%m-%d %H:%M:%S"))

print('....')
print(datetime.datetime.now()) #返回 2023-1-20 13:40:29.151057
print(datetime.date.fromtimestamp(time.time()) )  # 时间戳直接转成日期格式 2023-1-20
print(datetime.datetime.now())
print(datetime.datetime.now() + datetime.timedelta(3)) #当前时间+3天
print(datetime.datetime.now() + datetime.timedelta(-3)) #当前时间-3天
print(datetime.datetime.now() + datetime.timedelta(hours=3)) #当前时间+3小时
print(datetime.datetime.now() + datetime.timedelta(minutes=30)) #当前时间+30分

print(datetime.date.fromtimestamp(time.time()))  # 2023-1-20

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