Python - Convert String to datetime object and Convert datetime to String and timedalta - 字串轉日期、日期轉字串、日的加減

Version

Python version ：Python 3.6.0 :: Anaconda 4.3.1 (64-bit)
System version ：Windows 10

Code:

from datetime import datetime,timedelta
string_date = '20170727'
# Convert String to datetime object - 字串轉日期
datetime_date = datetime.strptime(string_date, "%Y%m%d").date()

# 日期的加減法
date_sub_1 = datetime_date - timedelta(1)

# Convert datetime to String - 日期轉字串 
date_sub_1_string = date_sub_1.strftime("%Y-%m-%d")

print('datetime_date :',datetime_date,'\t,type :',type(datetime_date))
print('date_sub_1 :',date_sub_1,'\t,type :',type(date_sub_1))
print('date_sub_1_string :',date_sub_1_string,'\t,type :',type(date_sub_1_string))

Result：

datetime_date : 2017-07-27     ,type : <class 'datetime.date'>
date_sub_1 : 2017-07-26     ,type : <class 'datetime.date'>
date_sub_1_string : 2017-07-26     ,type : <class 'str'>

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