datetime - How to convert string date (Jan 25, 2021) to y-m-d date (2021-01-01) in python

Question

I have strings like Jan 25, 2021 (Jan,Feb,Mar,May,Jun,Jul,Aug,Sep,Oct,Nov,Dec) how can I convert it to 2021-01-25?

I was defining a function like:

def to_datetime(datestring):  
    
    #date = datetime.strptime(datestring, '%m.%d.%Y')
    #return date.strftime("%Y-%m-%d")
    
    return datetime.strptime(datestring, '%Y-%m-%d')

The issue are the month words so maybe I can replace the string to month number and then convert it but I am stuck

question from:https://stackoverflow.com/questions/65894575/how-to-convert-string-date-jan-25-2021-to-y-m-d-date-2021-01-01-in-python

Answer 1

As you can see in my comment, you just need to use the right matching mask to get it right.

Your date strings are in the format %b %d, %Y, so you need to use the same mask in strptime(). With that in mind, a function like this will do the job:

from datetime import datetime


def mdy_to_ymd(d):
    return datetime.strptime(d, '%b %d, %Y').strftime('%Y-%m-%d')

And here is a proof of concept:

>>> from datetime import datetime
>>> 
>>> 
>>> def mdy_to_ymd(d):
...     return datetime.strptime(d, '%b %d, %Y').strftime('%Y-%m-%d')
... 
>>> mdy_to_ymd('Jan 25, 2021')
'2021-01-25'
>>> 

Bear in mind that strptime() creates a datetime object from a string matching a date using masking characters format. Once you get the right mask and the right representation in a datetime object, you can convert it to the desired format using strftime().

For more information, check strftime() and strptime() Format Codes.