python獲取時間

通過調用下面的方法獲取想要獲得的時間，時間格式爲yyyy-MM-dd

# encoding: utf-8
import datetime


def get_curmonth_firstday():
    """
    獲取當月第一天
    :return:
    """
    return datetime.date(datetime.date.today().year,datetime.date.today().month,1)


def get_lastmonth_lastday():
    """
    獲取上月最後一天
    :return:
    """
    return get_curmonth_firstday() - datetime.timedelta(days=1)


def get_lastmonth_firstday():
    """
    獲取上月第一天
    :return:
    """
    return datetime.date(get_lastmonth_lastday().year, get_lastmonth_lastday().month, 1)


def get_premonth_firstday(num):
    """
    獲取前幾個月第一天
    :param num: 月份數
    :return:
    """
    i = 1
    day = get_curmonth_firstday()
    while(i <= num):
        day = day - datetime.timedelta(days=1)
        day = datetime.date(day.year, day.month, 1)
        i = i + 1
    return day


def get_premonth_lastday(num):
    """
    獲取前幾個月最後一天
    :param num: 月份數
    :return:
    """
    i = 1
    day = get_curmonth_firstday()
    while(i <= num):
        day = datetime.date(day.year, day.month, 1)
        day = day - datetime.timedelta(days=1)
        i = i + 1
    return day


def get_preday(num):
    """
    獲取前幾天
    :param num: 天數
    :return:
    """
    i = 1
    while(i <= num):
        today = datetime.date.today()
        day = today - datetime.timedelta(days=num)
        i = i + 1
    return day


def get_today():
    """
    獲取今天
    :return:
    """
    return datetime.date.today()

def get_prespcday(spcday, num):
    """
    獲取前幾天
    :param num: 天數
    :return:
    """
    i = 1
    while(i <= num):
        spcday1 = datetime.datetime.strptime(spcday, "%Y-%m-%d")
        day = spcday1 - datetime.timedelta(days=num)
        i = i + 1
    return str(day).split(' ')[0]


def get_nextspcday(spcday, num):
    """
    獲取前幾天
    :param num: 天數
    :return:
    """
    i = 1
    while(i <= num):
        spcday1 = datetime.datetime.strptime(spcday, "%Y-%m-%d")
        day = spcday1 + datetime.timedelta(days=num)
        i = i + 1
    return str(day).split(' ')[0]