Python 如何將字串轉換為時間日期 datetime 格式

本教程來介紹 Python 如何將字串 string 轉換為 datetime 物件,隨後列舉出來程式碼例子來實現流行的時間格式的轉化。

datetime.strptime()

在以前的教程中,我們介紹了使用 datetime.strftime() 方法將 datetime 轉化為字串。這裡我們將用 datetime.strptime() 方法來實現逆轉換。兩種方法中的差別 fp 分別對應著 format(格式)和 parse(解析)。

datetime.strptime() 按照給定的 datetime 格式來解析字串,解析成功的話,返回 datetime 物件。

下面的例子是 datetime.strptime() 的簡單使用例子。

from datetime import datetime

datetime.strptime("2018-01-31", "%Y-%m-%d")

它的返回結果是,

datetime.datetime(2018, 1, 31, 0, 0)

The directives of the string format codes are listed here for your reference

Directive Meaning Example
%a Weekday as locale’s abbreviated name. Sun, Mon, …, Sat (en_US);So, Mo, …, Sa (de_DE)
%A Weekday as locale’s full name. Sunday, Monday, …, Saturday (en_US);Sonntag, Montag, …, Samstag (de_DE)
%w Weekday as a decimal number, where 0 is Sunday and 6 is Saturday. 0, 1, …, 6
%d Day of the month as a zero-padded decimal number. 01, 02, …, 31
%b Month as locale’s abbreviated name. Jan, Feb, …, Dec (en_US);Jan, Feb, …, Dez (de_DE)
%B Month as locale’s full name. January, February, …, December (en_US);Januar, Februar, …, Dezember (de_DE)
%m Month as a zero-padded decimal number. 01, 02, …, 12
%y Year without century as a zero-padded decimal number. 00, 01, …, 99
%Y Year with century as a decimal number. 0001, 0002, …, 2013, 2014, …, 9998, 9999
%H Hour (24-hour clock) as a zero-padded decimal number. 00, 01, …, 23
%I Hour (12-hour clock) as a zero-padded decimal number. 01, 02, …, 12
%p Locale’s equivalent of either AM or PM. AM, PM (en_US);am, pm (de_DE)
%M Minute as a zero-padded decimal number. 00, 01, …, 59
%S Second as a zero-padded decimal number. 00, 01, …, 59
%f Microsecond as a decimal number, zero-padded on the left. 000000, 000001, …, 999999
%z UTC offset in the form ±HHMMSS. (empty), +0000, -0400, +1030
%Z Time zone name (empty string if the object is naive). (empty), UTC, EST, CST
%j Day of the year as a zero-padded decimal number. 001, 002, …, 366
%U Week number of the year (Sunday as the first day of the week) as a zero padded decimal number. All days in a new year preceding the first Sunday are considered to be in week 0. 00, 01, …, 53
%W Week number of the year (Monday as the first day of the week) as a decimal number. All days in a new year preceding the first Monday are considered to be in week 0. 00, 01, …, 53
%c Locale’s appropriate date and time representation. Tue Aug 16 21:30:00 1988 (en_US);Di 16 Aug 21:30:00 1988 (de_DE)
%x Locale’s appropriate date representation. 08/16/88 (None);08/16/1988 (en_US);16.08.1988 (de_DE)
%X Locale’s appropriate time representation. 21:30:00 (en_US);21:30:00 (de_DE)
%% A literal '%' character. %

datetime.strptime() 舉例

7-May-2013 格式

from datetime import datetime

dateString = "7-May-2018"
dateFormatter = "%u-%b-%Y"
datetime.strptime(dateString, dateFormatter)

輸出為,

datetime.datetime(2013, 5, 1, 0, 0)

31/12/2018 格式

from datetime import datetime

dateString = "31/12/2013"
dateFormatter = "%d/%m/%Y"
datetime.strptime(dateString, dateFormatter)

輸出

datetime.datetime(2013, 12, 31, 0, 0)

Mon, July 16 2018格式

from datetime import datetime

dateString = "31/12/2013"
dateFormatter = "%d/%m/%Y"
datetime.strptime(dateString, dateFormatter)

輸出

datetime.datetime(2018, 7, 16, 0, 0)

Monday, July 16, 2018 20:01:56 格式

from datetime import datetime

dateString = "Monday, July 16, 2018 20:01:56"
dateFormatter = "%A, %B %d, %Y %H:%M:%S"
datetime.strptime(dateString, dateFormatter)

輸出

datetime.datetime(2018, 7, 16, 20, 1, 56)