Python - Get Yesterday's date as a string in YYYY-MM-DD format

Question

As an input to an API request I need to get yesterday's date as a string in the format YYYY-MM-DD. I have a working version which is:

yesterday = datetime.date.fromordinal(datetime.date.today().toordinal()-1) report_date = str(yesterday.year) + \    ('-' if len(str(yesterday.month)) == 2 else '-0') + str(yesterday.month) + \    ('-' if len(str(yesterday.day)) == 2 else '-0') + str(yesterday.day) 

There must be a more elegant way to do this, interested for educational purposes as much as anything else!

Answer 1

You Just need to subtract one day from today's date. In Python datetime.timedelta object lets you create specific spans of time as a timedelta object.

datetime.timedelta(1) gives you the duration of "one day" and is subtractable from a datetime object. After you subtracted the objects you can use datetime.strftime in order to convert the result --which is a date object-- to string format based on your format of choice:

>>> from datetime import datetime, timedelta >>> yesterday = datetime.now() - timedelta(1)  >>> type(yesterday)                                                                                                                                                                                     >>> datetime.datetime      >>> datetime.strftime(yesterday, '%Y-%m-%d') '2015-05-26' 

Note that instead of calling the datetime.strftime function, you can also directly use strftime method of datetime objects:

>>> (datetime.now() - timedelta(1)).strftime('%Y-%m-%d') '2015-05-26' 

As a function:

def yesterday(string=False, frmt='%Y-%m-%d'):     yesterday = datetime.now() - timedelta(1)     if string:         return yesterday.strftime(frmt)     return yesterday