Helpful reusable functions for working with datetime objects

datetime_functions.py

import datetime
import pytz
import dateutil
import os

def datetime_to_str(datetime_obj, date_format="%Y_%m_%d_%H_%M_%S"):
    """Convert a `datetime.datetime` object to a string in the desired format.

    Reference for string formatting dates available here:
        http://strftime.org/
    """
    return datetime_obj.strftime(date_format)

def str_to_datetime(str_datetime, date_format=None, **kwargs):
    """Convert a string datetime representation to a `datetime.datetime` object.
    If the format is known it can be passed as an argument, e.g. "%d/%m/%Y",
    otherwise it will be guessed by `dateutil.parser.parse`, for which kwargs
    can be passed.

    Reference for string formatting dates available here:
        http://strftime.org/
    """
    if not date_format:
        dt = dateutil.parser.parse(str_datetime, **kwargs)
    else:
        dt = datetime.datetime.strptime(str_datetime, date_format)
    return dt

def formatted_str_now(date_format="%Y_%m_%d_%H_%M_%S", timezone="US/Eastern"):
    """Get a string representation of the current time in the desired format.

    Reference for string formatting dates available here:
        http://strftime.org/

    A list of available timezones can be found by checking `pytz.all_timezones`.
    """
    UTC_now = pytz.utc.localize(datetime.datetime.utcnow())
    TZ_now = UTC_now.astimezone(pytz.timezone(timezone)).strftime(date_format)
    return TZ_now

def get_file_modified_date(fp):
    """Get the datetime stamp of when a file was last modified.

    Args:
        fp (str): filepath.
    """
    unix_time = os.path.getmtime(fp)
    return datetime.datetime.fromtimestamp(unix_time)