只是为了好玩，一个使用divmod的纯数学答案。因为是乘法运算，所以它的效果很差，可以简单地检查月份的个数(如果等于12，则增加年份等)

year = today.year
month = today.month

nm = list(divmod(year * 12 + month + 1, 12))
if nm[1] == 0:
    nm[1] = 12
    nm[0] -= 1
pm = list(divmod(year * 12 + month - 1, 12))
if pm[1] == 0:
    pm[1] = 12
    pm[0] -= 1

next_month = nm
previous_month = pm

from datetime import date, timedelta

first_day_of_current_month = date.today().replace(day=1)
last_day_of_previous_month = first_day_of_current_month - timedelta(days=1)

print "Previous month:", last_day_of_previous_month.month

Or:

from datetime import date, timedelta

prev = date.today().replace(day=1) - timedelta(days=1)
print prev.month

对于那些来到这里，并希望获得前一个月的第一天和最后一天的人:

from datetime import date, timedelta

last_day_of_prev_month = date.today().replace(day=1) - timedelta(days=1)

start_day_of_prev_month = date.today().replace(day=1) - timedelta(days=last_day_of_prev_month.day)

# For printing results
print("First day of prev month:", start_day_of_prev_month)
print("Last day of prev month:", last_day_of_prev_month)

输出:

First day of prev month: 2019-02-01
Last day of prev month: 2019-02-28

您来这里可能是因为您正在NiFi中使用Jython。这就是我最终实现它的方式。我稍微偏离了Robin Carlo Catacutan的答案，因为访问last_day_of_prev_month。由于这里解释的Jython数据类型问题，由于某种原因，这个问题似乎存在于NiFi的Jython中，但不存在于vanilla Jython中。

from datetime import date, timedelta
import calendar
    
flowFile = session.get()
    
if flowFile != None:

    first_weekday_in_prev_month, num_days_in_prev_month = calendar.monthrange(date.today().year,date.today().month-1)

    last_day_of_prev_month = date.today().replace(day=1) - timedelta(days=1)
    first_day_of_prev_month = date.today().replace(day=1) - timedelta(days=num_days_in_prev_month)
            
    last_day_of_prev_month = str(last_day_of_prev_month)
    first_day_of_prev_month = str(first_day_of_prev_month)
    
    flowFile = session.putAllAttributes(flowFile, {
        "last_day_of_prev_month": last_day_of_prev_month,
        "first_day_of_prev_month": first_day_of_prev_month
    })
    
session.transfer(flowFile, REL_SUCCESS)

from datetime import datetime, timedelta, time, timezone

current_time = datetime.now(timezone.utc)
last_day_previous_month = datetime.combine(current_time.replace(day=1), time.max) - timedelta(days=1)
first_day_previous_month = datetime.combine(last_day_previous_month, time.min).replace(day=1)

输出:

first_day_previous_month: 2022-02-01 00:00:00 
last_day_previous_month: 2022-02-28 23:59:59.999999

有一个高级库dateparser，可以确定给定自然语言的过去日期，并返回相应的Python datetime对象

from dateparser import parse
parse('4 months ago')