Parse multiple date formats to a specific format

Question

In my application user can enter dates in format of dd/mm/yy with date separator variations(like they can use /,- or space as a seperator). They can also put 4 digit year or 2 digit year and they can also enter 3 letter code for a month or a 2 digit code for month. Once I have the date from the user I want to validate that the format is a valid date format and then convert it to '%d-%b-%Y'. In the below function I am validating the date format, but I am not sure how to handle all the mixed date separator formats like 01/12 2013, 01-12 13, 01 12/2013 etc. There can be loads of these

def validate_date(date_str):
    formats = ['%d-%b-%Y', '%d-%b-%y', '%d-%m-%Y', '%d-%m-%y',
               '%d/%m/%Y', '%d/%m/%y', '%d/%b/%Y', '%d/%b/%y',
               '%d %m %Y', '%d %m %y', '%d %b %Y', '%d %b %y',
                '%d%m%Y', '%d%b%y', '%d%b%Y', '%d %b/%Y'] 
    data = None

    for fmt in formats:
        try:
            dateValue = datetime.datetime.strptime(date_str, fmt).date()
            data = dateValue
            break
        except ValueError:
            pass

    if data is None:
    # invalid date format

Answer 1

You can replace all chars not being digit into spaces and then parse it using much less formats.