Python DateTime – strptime()函数

strptime()是 DateTime 中可用的另一种方法，用于将字符串格式的时间戳格式化为日期时间对象。

Syntax: datetime.strptime(time_data, format_data)

Parameter:

• time_data is the time present in string format
• format_data is the data present in datetime format which is converted from time_data using this function.

strptime() 如何工作？

这个函数有两个参数，其中一些时间被赋予的字符串和一个格式码，改变字符串入，该字符串被改变为DateTime对象按照下面给出的代码的列表。

格式代码

format code	meaning	example
%a	Abbreviated weekday name	Sun, Mon
%A	Full weekday name	Sunday, Monday
%w	Weekday as decimal number	0…6
%d	Day of the month as a zero-padded decimal	01, 02
%-d	day of the month as decimal number	1, 2..
%b	Abbreviated month name	Jan, Feb
%m	month as a zero padded decimal number	01, 02
%-m	month as a decimal number	1, 2
%B	Full month name	January, February
%y	year without century as a zero padded decimal number	99, 00
%-y	year without century as a decimal number	0, 99
%Y	year with century as a decimal number	2000, 1999
%H	hour(24 hour clock) as a zero padded decimal number	01, 23
%-H	hour(24 hour clock) as a decimal number	1, 23
%I	hour(12 hour clock) as a zero padded decimal number	01, 12
%-I	hour(12 hour clock) as a decimal number	1, 12
%p	locale’s AM or PM	AM, PM
%M	Minute as a zero padded decimal number	01, 59
%-M	Minute as a decimal number	1, 59
%S	Second as a zero padded decimal number	01, 59
%-S	Second as a decimal number	1, 59
%f	microsecond as a decimal number, zero padded on the left side	000000, 999999
%z	UTC offset in the form +HHMM or -HHMM
%Z	Time zone name
%j	day of the year as a zero padded decimal number	001, 365
%-j	day of the year as a decimal number	1, 365
%U	Week number of the year (Sunday being the first)	0, 6
%W	Week number of the year	00, 53
%c	locale’s appropriate date and time representation	Mon Sep 30 07:06:05 2013
%x	locale’s appropriate date representation	11/30/98
%X	locale’s appropriate time representation	10:03:43
%%	A literal ‘%’ character	%

示例 1：使用 strptime 读取日期时间并获取所有时间数据的Python程序。这里我们将获取字符串格式的时间数据并提取小时、分钟、秒和毫秒

Python3

# import datetime module from datetime
from datetime import datetime
 
# consider the time stamp in string format
# DD/MM/YY H:M:S.micros
time_data = "25/05/99 02:35:5.523"
 
# format the string in the given format :
# day/month/year hours/minutes/seconds-micro
# seconds
format_data = "%d/%m/%y %H:%M:%S.%f"
 
# Using strptime with datetime we will format
# string into datetime
date = datetime.strptime(time_data, format_data)
 
# display milli second
print(date.microsecond)
 
# display hour
print(date.hour)
 
# display minute
print(date.minute)
 
# display second
print(date.second)
 
# display date
print(date)

输出：

523000

2

35

5

1999-05-25 02:35:05.523000

示例 2：使用 strptime 的Python代码。这里我们将采用字符串格式的时间数据，并以“%d/%m/%y %H:%M:%S.%f”格式提取时间戳。

蟒蛇3

# import datetime module from datetime
from datetime import datetime
 
# consider the time stamps from a list  in string
# format DD/MM/YY H:M:S.micros
time_data = ["25/05/99 02:35:8.023", "26/05/99 12:45:0.003",
             "27/05/99 07:35:5.523", "28/05/99 05:15:55.523"]
 
# format the string in the given format : day/month/year 
# hours/minutes/seconds-micro seconds
format_data = "%d/%m/%y %H:%M:%S.%f"
 
# Using strptime with datetime we will format string
# into datetime
for i in time_data:
    print(datetime.strptime(i, format_data))

输出：

1999-05-25 02:35:08.023000

1999-05-26 12:45:00.003000

1999-05-27 07:35:05.523000

1999-05-28 05:15:55.523000

我们可以通过使用 strptime() 本身来获取遵循所有日期结构的时间。

语法：

time.strptime(Timestamp, ‘%d/%m/%y %H:%M:%S’)

其中时间戳包括时间和日期

示例：在结构中获取时间的Python代码：

蟒蛇3

#import time
import time
 
# get data of 4 th april 2021  at time 9 pm
print(time.strptime('04/04/21 09:31:22', '%d/%m/%y %H:%M:%S'))
 
# get data of 5 th april 2021  at time 9 pm
print(time.strptime('05/04/21 09:00:42', '%d/%m/%y %H:%M:%S'))
 
# get data of 6 th april 2021  at time 9 pm
print(time.strptime('06/04/21 09:11:42', '%d/%m/%y %H:%M:%S'))
 
# get data of 7 th april 2021  at time 9 pm
print(time.strptime('07/04/21 09:41:12', '%d/%m/%y %H:%M:%S'))

输出：

time.struct_time(tm_year=2021, tm_mon=4, tm_mday=4, tm_hour=9, tm_min=31, tm_sec=22, tm_wday=6, tm_yday=94, tm_isdst=-1)

time.struct_time(tm_year=2021, tm_mon=4, tm_mday=5, tm_hour=9, tm_min=0, tm_sec=42, tm_wday=0, tm_yday=95, tm_isdst=-1)

time.struct_time(tm_year=2021, tm_mon=4, tm_mday=6, tm_hour=9, tm_min=11, tm_sec=42, tm_wday=1, tm_yday=96, tm_isdst=-1)

time.struct_time(tm_year=2021, tm_mon=4, tm_mday=7, tm_hour=9, tm_min=41, tm_sec=12, tm_wday=2, tm_yday=97, tm_isdst=-1)

也可以以 yyyy-mm-dd 日期时间格式获取字符串日期时间。 yyyy-mm-dd 代表年-月-日。我们可以使用 strptime()函数将字符串格式转换为 DateTime。我们将使用 '%Y/%m/%d' 格式将字符串为日期时间。

Syntax: datetime.datetime.strptime(input,format)

Parameter:

• input is the string datetime
• format is the format – ‘yyyy-mm-dd’
• datetime is the module

首先，导入模块并给出输入日期时间字符串。现在使用 strptime 获取所需的格式并使用 date()函数从 DateTime 获取日期

示例 1 ：将字符串日期时间格式转换为日期时间的Python程序

蟒蛇3

# import the datetime module
import datetime
 
# datetime in string format for may 25 1999
input = '2021/05/25'
 
# format
format = '%Y/%m/%d'
 
# convert from string format to datetime format
datetime = datetime.datetime.strptime(input, format)
 
# get the date from the datetime using date()
# function
print(datetime.date())

输出：

2021-05-25

示例 2：将字符串日期时间列表转换为日期时间

蟒蛇3

# import the datetime module
import datetime
 
# datetime in string format for list of dates
input = ['2021/05/25', '2020/05/25', '2019/02/15', '1999/02/4']
 
# format
format = '%Y/%m/%d'
for i in input:
   
    # convert from string format to datetime format
    # and get the date
    print(datetime.datetime.strptime(i, format).date())

输出：

2021-05-25

2020-05-25

2019-02-15

1999-02-04

我们还可以以“%d/%m/%Y %H:%M:%S”格式显示日期时间。为此，我们将以日期-月-年小时：分钟；秒格式获取数据。所以我们必须输入日期时间字符串并获得这种格式

Syntax: datetime.strptime(input_date, “%d/%m/%Y %H:%M:%S”)

Parameter:

• datetime is the module
• input_date is the string datetime format
• strptime is used to convert input_date string into datetime

示例3： Python程序将字符串日期时间转换为“%d/%m/%Y %H:%M:%S”格式

蟒蛇3

#import datetime
from datetime import datetime
 
# consider the datetime string in dd/mm/yyyy
# hh:mm:ss format
date = "25/05/2021 02:35:15"
 
# convert string datetime to  dd/mm/yyyy hh:mm:ss
# format
datetime_date = datetime.strptime(date, "%d/%m/%Y %H:%M:%S")
print(datetime_date)

输出：

2021-05-25 02:35:15