How to validate a specific Date and Time format using Python

Question

I am writing a program to validate portions of an XML file. One of the points I would like to validate is a Date Time format. I've read up on the forum about using time.strptime() but the examples weren't quite working for me and were a little over my expertise. Anyone have any ideas how I could validate the following. This is the format the date and time must be in.

2/26/2009 3:00 PM

I am sure there is something built-in and very easy but I can't find. Many thanks if you've run by this before and have suggestions.

What do you mean validate the datetime? Do you want to ensure it is properly formatted, an actual date that makes sense (i.e. not 13/45/20000), fits some other criteria? What do you want to do with the datetime data after "validation"? — wflynny, Aug 30 '13 at 18:33

alecxe · Answer 1 · 2014-12-08T12:40:04.163

23

Yes, you can use datetime.strptime():

from datetime import datetime


def validate_date(d):
    try:
        datetime.strptime(d, '%m/%d/%Y %I:%M %p')
        return True
    except ValueError:
        return False


print validate_date('2/26/2009 3:00 PM')  # prints True
print validate_date('2/26/2009 13:00 PM')  # prints false
print validate_date('2/26/2009')  # prints False
print validate_date("Should I use regex for validating dates in Python?")  # prints False

edited Dec 08 '14 at 12:40

answered Aug 30 '13 at 18:33

alecxe

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Great answer. Following typical [EAFP](http://docs.python.org/2/glossary.html#term-eafp) style, the simplest and most robust way to test whether you can FOO a BAR is usually to just FOO it and see if it works… – abarnert Aug 30 '13 at 18:41
@abarnert thank you, asking for forgiveness is definitely easier! – alecxe Aug 30 '13 at 18:46

score 3 · Answer 2 · edited Aug 30 '13 at 19:00

3

This is how you do it:

    from datetime import datetime

    def validate(datetime_string):
        try:
            return datetime.strptime(datetime_string,"%m/%d/%Y %I:%M %p")
        except ValueError:
            return False

edited Aug 30 '13 at 19:00

Daniel Mann

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answered Aug 30 '13 at 18:35

Srinivas Reddy Thatiparthy

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score 1 · Answer 3 · answered Aug 30 '13 at 18:41

1

import datetime
parsed = datetime.datetime.strptime("2/26/2009 3:00 PM", r'%m/%d/%Y %H:%M %p')
iso_formatted = parsed.isoformat()
print(iso_formatted)

answered Aug 30 '13 at 18:41

m.kocikowski

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score 0 · Answer 4 · answered Aug 30 '13 at 18:34

You could use locale module combined with time.strptime() to ensure the date/time is in the proper order (month, day, year, etc). Or, you could do simple regex...

pattern = re.compile(r'\d{1,2}/\d{1,2}/\d{4} \d{1,2}:\d{2} (AM|PM)') ...I am not a regex pro lol, there's probably a better pattern.

You can also use the datetime module and create a new datetime object with the locale constant and have it convert the numbers to their proper type (day, month, year).

Good luck!

How to validate a specific Date and Time format using Python

4 Answers4

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