python date utils: yesterday, dateAdd, dateSub, dateRange

dateUtils.py

def get_yesterday(n_days_ago=1, FMT='%Y-%m-%d'):
    import datetime
    return datetime.datetime.strftime(
        datetime.datetime.now() - datetime.timedelta(n_days_ago), FMT
    )


def dateAdd(thedate, num, FMT='%Y-%m-%d'):
    import datetime
    strptime, strftime = datetime.datetime.strptime, datetime.datetime.strftime
    return strftime(strptime(thedate, FMT) + datetime.timedelta(num), FMT)


def dateSub(thedate, num, FMT='%Y-%m-%d'):
    return dateAdd(thedate, -num, FMT)

def dateRange(start, end, end_include=False, step=1, FMT="%Y-%m-%d"):
    import datetime
    strptime, strftime = datetime.datetime.strptime, datetime.datetime.strftime
    days = (strptime(end, FMT) - strptime(start, FMT)).days
    days = days + int(step/abs(step)) if end_include else days  # +1 OR -1
    return [strftime(strptime(start, FMT) + datetime.timedelta(i), FMT) for i in range(0, days, step)]

def dateDiff(end_date, start_dt, FMT='%Y-%m-%d'):
    import datetime
    strptime, strftime = datetime.datetime.strptime, datetime.datetime.strftime
    return (strptime(end_date, FMT) - strptime(start_dt, FMT)).days