How to validate a specific Date and Time format using Python

问题

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.

回答1:

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

回答2:

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

回答3:

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)

回答4:

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!

来源：https://stackoverflow.com/questions/18539266/how-to-validate-a-specific-date-and-time-format-using-python

标签

python

datetime

format