reformat_date.py

"""
Module to convert an array of dates into ISO format.
Author: Alexander Scheibler
"""

import datetime
import re

def reformat_date(dates):
    """
    Converts an array of dates to ISO format.
    Ex: '26th Dec 2061' to '2061-12-26'.
    args:
        dates: array of dates in the format %d-%b-%Y
    """

    reformated_dates = []

    for item in dates:
        # Check type explicitly
        if not isinstance(item, str):
            raise TypeError(f'Expected string, got {type(item).__name__}')

        # Fix Whitespace
        item = item.strip()

        day, month, year = item.split(' ')
        day_numbers = re.compile(r'\d+')

        # Fix wrong patterns such as '23rdx'
        suffix = re.sub(r'\d+', '', day)
        if suffix not in ('st', 'nd', 'rd', 'th'):
            raise ValueError(f"Invalid day suffix: '{suffix}'")

        day = day_numbers.findall(day)[0]
        formatted_date = datetime.datetime.strptime(f'{year}-{month}-{day}',
                                                    '%Y-%b-%d')
        reformated_dates.append(
            datetime.date(formatted_date.year,
                          formatted_date.month,
                          formatted_date.day).isoformat())

    return reformated_dates

print(reformat_date(['25th May 1912', '16th Dec 2018', '26th Dec 2061']))