python -- datetime library usage

datetime.date: class representing date -- Date object

datetime.date(year,month,day), return year month day

print(datetime.date(2021,9,13)) result: 2021-09-13

datetime.date.today(), get the year, month and day of the current day, and return year month day

print(datetime.date.today()) result: 2021-09-13 a = datetime.date.today() print(a.year) print(a.month) print(a.day) result: 2021 9 13

datetime.date.isocalendar(), so that the date used conforms to the ISO standard, and returns a tuple containing three values: year year, week number, weeks (Monday is 1... Sunday is 7)

print(datetime.date.today().isocalendar()) result: (2021, 37, 1)

datetime.date.isoformat(), return the date string conforming to ISO 8601 standard (YYYY-MM-DD);

print(datetime.date.today().isoformat()) result: 2021-09-13

datetime.date.isoweekday(): returns the number of weeks (Monday is 1... Sunday is 7) of the specified date conforming to the ISO standard

print(datetime.date.today().isoweekday()) result: 1

datetime.date.strftime(format): format the date and time according to the given format.

print(datetime.date.today().strftime("%Y %m %d")) result: 2021 09 13

datetime.date.ctime(), returns the time format in English. The standard format is Mon Sep 13 00:00:00 2021

print(datetime.date.today().ctime()) result: Mon Sep 13 00:00:00 2021

datetime.datetime: class representing date and time - date and time object (most commonly used)

datetime class is actually a combination of date class and time class. Most of its methods and properties are inherited from these two classes
The datetime class has many parameters. datetime(year, month, day[, hour[, minute[, second[, microsecond[,tzinfo]]]]) returns year, month, day, hour, minute and second

datetime.datetime.now(): returns the current system time

print(datetime.datetime.now()) result: 2021-09-13 23:08:13.415655

datetime.datetime.ctime() converts datetime.datetime type to str type, output: Sun Jul 28 15:47:51 2019

print(datetime.datetime.now().ctime()) result: Mon Sep 13 23:08:44 2021

datetime.datetime.now().date(): returns the date part of the current date and time

print(datetime.datetime.now().date()) result: 2021-09-13

datetime.datetime.now().time(): returns the time part of the current date and time

print(datetime.datetime.now().time()) result: 23:10:54.719265

Datetime. Datetime. Utctimetaple(): returns the UTC time tuple

print(datetime.datetime.now().utctimetuple()) result: time.struct_time(tm_year=2021, tm_mon=9, tm_mday=13, tm_hour=23, tm_min=11, tm_sec=52, tm_wday=0, tm_yday=256, tm_isdst=0)

datetime.datetime.combine(date,time): merge a date object and a time object to generate a datetime object:

a = datetime.datetime.now() print(datetime.datetime.combine(a.date(),a.time())) result: 2021-09-13 23:14:31.712160

datetime.datetime.strftime(format): convert from date format to string format

print(datetime.datetime.now().strftime('%b-%d-%Y %H:%M:%S')) result: Sep-13-2021 23:20:10

datetime.datetime.strptime(string, format): convert from string format to date format

print(datetime.datetime.strptime('Sep-13-2021 23:20:10', '%b-%d-%Y %H:%M:%S')) result: 2021-09-13 23:20:10

datetime.time: class representing time -- time object

The time class consists of hour hour, minute minute, second second, microsecond millisecond and tzinfo
time([hour[, minute[, second[, microsecond[, tzinfo]]]]])

>>> a = datetime.time(12,20,59,899) >>> a datetime.time(12, 20, 59, 899) >>> a.hour 12 >>> a.minute 20 >>> a.second 59 >>> a.microsecond 899

1.datetime.time.replace()
2.datetime.time.strftime(format): returns the time in format format
3.datetime.time.tzname(): returns the name of the time zone
4. Datetime. Time. Utoffset(): returns the time offset of the time zone

datetime.timedelta: represents the time interval, that is, the interval between two time points

The timedelta class is used to calculate the difference between two datetime objects.
This class contains the following attributes:
1. Days: days
2. Microseconds: microseconds (> = 0 and < 1 second)
3. Seconds: seconds (> = 0 and < 1 day)
days, seconds, microseconds, milliseconds, minutes, hours, weeks, and the default value is 0.

#Find the time two days and ten hours ahead of the current time delta = datetime.timedelta(days = 2,hours = 2) print(datetime.datetime.now()) print(datetime.datetime.now()-delta) result: 2021-09-14 11:40:27.702018 2021-09-12 09:40:27.702018

datetime.tzinfo: information about time zone

To be added, I think it's useless

Gets the date, hour, minute and second of the time of the day

#Gets the date, hour, minute and second of the time of the day print(datetime.datetime.now()) #Get the date, hour, minute and second of the time of the day method 1 print(datetime.datetime.now().date()) #Get the date, hour, minute and second of the time of the day method 2 print(datetime.date.today()) #Gets the date, hour, minute and second of the time of the day print(datetime.datetime.now().time()) result: 2021-09-14 11:52:52.459443 2021-09-14 2021-09-14 11:52:52.459443

Gets the date of the first and last day of the previous month

# Get the date of the current time first today = datetime.date.today() # Subtract one day from the last day of the previous month, that is, the first day of the current month lastday = datetime.date(today.year,today.month,1)-datetime.timedelta(days=1) # First day of last month firstday = datetime.date(today.year,today.month-1,1) print(lastday) print(firstday) result: 2021-08-31 2021-08-01

Get time difference

start = datetime.datetime.now() time.sleep(2) end = datetime.datetime.now() print((end - start).seconds) result: 2

Find the time two days and ten hours ahead of the current time

You can calculate: days, hours, minutes, seconds, and microseconds

delta = datetime.timedelta(days = 2,hours = 2) print(datetime.datetime.now()) print(datetime.datetime.now()-delta) result: 2021-09-14 11:40:27.702018 2021-09-12 09:40:27.702018

Calculate the date of the last day of the month and the number of days of the month on the specified date

# Calculate the last day of the current month, i.e. the first day of the next month - day 1 def eomonth(date_object): # First, we have to judge whether the current time is the last month of each year if date_object.month == 12: # In December, year+1 and month is 1 next_month_first_date = datetime.date(date_object.year+1,1,1) else: # If it is not December, then month+1 next_month_first_date = datetime.date(date_object.year, date_object.month+1, 1) return next_month_first_date - datetime.timedelta(1) date = datetime.date.today() print(eomonth(date)) print(eomonth(date).day) result: 2021-09-30 30

Calculates the date of the month following the specified date

# Calculate the last day of the current month, i.e. the first day of the next month - day 1 def eomonth(date_object): # First, we have to judge whether the current time is the last month of each year if date_object.month == 12: # In December, year+1 and month is 1 next_month_first_date = datetime.date(date_object.year+1,1,1) else: # If it is not December, then month+1 next_month_first_date = datetime.date(date_object.year, date_object.month+1, 1) return next_month_first_date - datetime.timedelta(1) #Calculates the date of the month following the specified date def edate(date_object): # First, we have to judge whether the current time is the last month of each year if date_object.month == 12: # In December, year+1, month is 1, and day is date_object.day. In any case, date_object.day is 31 or less in January, and there will be no bug s in 31 days next_month_date = datetime.date(date_object.year+1, 1,date_object.day) else: # If it is not December, it needs to be discussed by situation, because there are large and small months. This month has the 31st day, but the next month does not necessarily have the first day of the next month next_month_first_day = datetime.date(date_object.year,date_object.month+1,1) # If the requested date is not in the next month, it will be replaced by the last day of the following month. Here, the function to obtain the number of days in the next month is called if date_object.day > eomonth(next_month_first_day).day: next_month_date = datetime.date(date_object.year,date_object.month+1,eomonth(next_month_first_day).day) else: next_month_date = datetime.date(date_object.year, date_object.month+1, date_object.day) return next_month_date date = datetime.date.today() print(date) print(edate(date)) result: 2021-09-14 2021-10-14

Obtain the time period from Monday to today and the corresponding time period of last week

today = datetime.date.today() this_monday = today - datetime.timedelta(today.isoweekday()-1) last_monday = this_monday - datetime.timedelta(7) last_weekday = today -datetime.timedelta(7) print(this_monday) print(today) print(last_monday) print(last_weekday) result: 2021-09-13 2021-09-14 2021-09-06 2021-09-07

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