将月份从 str 更改为 int 以进行计算

Question

我需要将月份从字符串值更改为整数值，以便进行计算。我正在使用可以提供当前日期的日期时间库，我需要将其与用户输入的日期进行比较，以找到整数形式的月份之间的差异。

import datetime

current_month = datetime.date.today().strftime('%B')
month_join = input('Please enter the month you joined')
month_difference = current_month - month_join

如果可能，我希望输入为一个月。如果没有，我将使用：

month_join = int(input('Please enter the month you joined')

Answer 1

听起来您需要的是一本将月份名称及其数值关联起来的字典。

import datetime

month_names = ["January",   "February", "March",    "April",
               "May",       "June",     "July",     "August",
               "September", "October",  "November", "December"]

months = {name : (index + 1) for index, name in enumerate(month_names)}

current_month    = datetime.date.today().strftime('%B')
month_joined     = input("Please enter the month you joined: ")
month_difference = abs(months[current_month] - months[month_joined])

print(month_difference)

您也可以通过使用calendar模块的month_name列表属性来完成字典的创建。

import datetime, calendar

months = {name : (index + 1) for index, name in enumerate(calendar.month_name[1:])}

current_month    = datetime.date.today().strftime('%B')
month_joined     = input("Please enter the month you joined: ")
month_difference = abs(months[current_month] - months[month_joined])

print(month_difference)

Answer 2

可能 datetime 中的 strptime 方法对你有一些用处。例如：

import datetime

current_month = datetime.date.today().strftime('%B')
month_join = datetime.datetime.strptime(input('Please enter the month you joined'), "%B")
month_difference = current_month.month - month_join.month

但请注意这一点 - 如果用户在上一个日历年加入会怎样？您最终会得到month_difference 的负值。

您最好实际获取用户加入的完整月份和年份，将其转换为 datetime 对象，从 datetime.today() 中减去它以获得 timedelta 对象。然后从该 timedelta 对象中获取月份计数。

您不妨尽可能多地利用日期时间库，而不是试图重新发明轮子。

Answer 3

如果用户第一次搞砸了，此方法允许用户多次输入正确答案。它还会检查以确保该数字是有效月份。您还可以添加检查以查看用户是否需要包含年份。 IE：如果current_month - month_join < 0 询问他们的年份。

import datetime

current_month = datetime.date.today().month
month_join = None
while month_join is None:
    month_join = raw_input('Please enter the month you joined:  ')
    if month_join == 'quit':
        exit(1)
    try:
        month_join = int(month_join)
        if month_join > 12 or month_join < 1 or not isinstance(month_join, int):
            print('Please enter a month value that is from 1 to 12')
            month_join = None
    except Exception as e:
        if isinstance(e, TypeError) or isinstance(e, ValueError):
            print('Please enter the month as an integer. IE. May = 5. If you want to close the program type "quit"')
            month_join = None
        else:
            raise e
month_difference = current_month - month_join
print month_difference

Answer 4

试试monthdelta 库。

import datetime
import monthdelta

current_month = datetime.date.today()
year = current_month.year
month_in = input('Please enter the month you joined')
month_dt = datetime.datetime.strptime(month_in, '%B').date()

# Construct new datetime object with current year
month_join = datetime.date(year=year, month=month_dt.month, day=1)

# Reduce year by one if the month occurs later
if month_join > current_month:
    month_join = datetime.date(year=year - 1, month=month_dt.month, day=1)

month_difference = monthdelta.monthmod(month_join, current_month)
print(month_difference[0].months)