python3 获取上个月、前几月、当前月的时间

#!/usr/bin/env python
# -*- coding: utf-8 -*-

import calendar
from datetime import datetime
from dateutil.relativedelta import relativedelta

# 获取当前月
def get_cur_month():
    return datetime.now().strftime("%Y-%m")

# 获取前几个月
def get_last_month(number=1):
    month_date = datetime.now().date() - relativedelta(months=number)
    return month_date.strftime("%Y-%m")

#获取上一个月的第一天,1号的0点0分0秒
def get_last_month_start(month_str=None):
    if not month_str:
        month_str = datetime.now().strftime('%Y-%m')
    year, month = int(month_str.split('-')[0]), int(month_str.split('-')[1])
    if month == 1:
        year -= 1
        month = 12
    else:
        month -= 1
    return '{}-{}-01 00:00:00'.format(year, month)

# 获取上一个月的最后一天的23点59分59秒
def get_last_month_end(month_str=None):
    if not month_str:
        month_str = datetime.now().strftime('%Y-%m')
    year, month = int(month_str.split('-')[0]), int(month_str.split('-')[1])
    if month == 1:
        year -= 1
        month = 12
    else:
        month -= 1
    end = calendar.monthrange(year, month)[1]
    return '{}-{}-{} 23:59:59'.format(year, month, end)