Python: datetime module summary

1 Introduction

Several classes defined in the datetime library:

class name	describe	common attributes
datetime.date	Indicates the date	year, month, day
datetime.time	Indicate time	hour, minute, second, microsecond
datetime.datetime	Indicates date and time	year, month, day, hour, minute, microsecond
datetime.timedelta	Represents the difference between two datetimes	days, hours, seconds
datetime.tzinfo	Abstract base class for describing time zone information objects	search online
datetime.timezone	Timezone, representing a fixed offset from UTC	datetime.timedelta object

For detailed methods and summary, refer to this article " datetime time and date module " 

2. Format the output string

The output string can be formatted as desired: datetime.datetime.strftime("format")

Code example:

import datetime
t = datetime.datetime.now()
print(t.strftime("%Y%m%d"),type(t.strftime("%Y%m%d")))
print(t.strftime("%Y-%m_%d:%H-%M:%S"))

# 输出
# 20220909 <class 'str'>
# 2022-09_09:10-41:33

instruction	significance	example
%a	abbreviation for local weekday	Sun, Mon, …, Sat
%A	Full name of the local weekday	Sunday, Monday, …, Saturday
%w	Weekday as a decimal number, where 0 means Sunday and 6 means Saturday	0, 1, …, 6
%d	The day of the month as a decimal number after zero padding	01, 02, …, 31
%b	local month abbreviation	an, Feb, …, Dec
%B	full name of the local month	January, February, …, December
%m	After zero padding, the month displayed as a decimal number	01, 02, …, 12
%y	Year without century in decimal number after padding with zeros	00, 01, …, 99
%Y	Year with century as a decimal number	0001, 0002, …, 2013, 2014, …, 9998, 9999
%H	Hour (24-hour clock)	00, 01, …, 23
%I	Hour (12-hour clock)	01, 02, …, 12
%M	Minutes as a decimal number after zero padding	00, 01, …, 59
%S	Seconds displayed as a decimal number after zero padding	00, 01, …, 59
%U	Week number of the year (Sunday as the first day of the week)	00, 01, …, 53
%W	Week number of the year (Monday as the first day of the week)	00, 01, …, 53
%c	localized appropriate date and time representation	Tue Aug 16 21:30:00 1988
%x	localized appropriate date representation	08/16/1988
%X	Appropriate time representation for localization	0.895833333
%%	Literal '%' characters	Literal '%' characters

 3. Commonly used codes

 1) Calculate the time difference:

import datetime
# 2022-04-24 10:51:23.677632
start_time = datetime.datetime(2022, 4, 24, 10, 51, 23, 677632)
# 2022-04-25 11:52:35.713161
end_time = datetime.datetime(2022, 4, 24, 10, 51, 24, 687638)
delta = end_time-start_time
# 获取timedelta对象经过单位换算后的总秒数
print("seconds: ", delta.seconds)
# 获取timedelta对象经过单位换算后的总微秒数
print("microseconds: ", delta.microseconds)
# 获取timedelta对象包含的总秒数
print("total_seconds: ", delta.total_seconds())
# 四舍五入，保留2位小数
print("total_seconds: ", round(delta.total_seconds(),2))

# 输出
# seconds:  1
# seconds:  10006
# total_seconds:  1.010006
# total_seconds:  1.01

Example of test timing:

import datetime
import time
start_time = datetime.datetime.now()
print("start_time:",start_time)
# 强制等待10秒时间,import time
time.sleep(10) 
end_time = datetime.datetime.now()
print("end_time:",end_time)
delta = end_time-start_time
# 获取timedelta对象经过单位换算后的总秒数
print("seconds: ", delta.seconds)
# 获取timedelta对象经过单位换算后的总微秒数
print("microseconds: ", delta.microseconds)
# 获取timedelta对象包含的总秒数
print("total_seconds: ", delta.total_seconds())
# 四舍五入，保留2位小数
print("total_seconds: ", round(delta.total_seconds(),2))

# 输出
start_time: 2022-09-09 10:54:49.917227
end_time: 2022-09-09 10:54:59.917423
seconds:  10
microseconds:  196
total_seconds:  10.000196
total_seconds:  10.0