目的：
Hi there, I'm trying to create a regular expression for the dash_core_components.Input "pattern" input property to validate year range inputs.
我有下面的Python v3.6.3代码，该代码提供用于输入格式验证的正则表达式（每位有效...）：
import datetime as dt
full_year_ = dt.datetime.now().year
mill_ = str(full_year_)[0]
century_ = str(full_year_)[1]
decade_ = str(int(str(full_year_)[2]))
prev_decade_ = str(int(str(full_year_)[2]) - 1)
year_ = str(full_year_)[3]
prior_decades = f'{mill_}{century_}[0-{prev_decade_}][0-9]'
current_decade = f'{mill_}{century_}{decade_}[0-{year_}]'
def century():
return f'^({prior_decades})|({current_decade})$'
def century_set():
# Acceptable Examples: 2018, 2019, 2020 | 2018:2020
return f'^\s*({prior_decades}|{current_decade})([,\s]+{prior_decades}|[,\s]+{current_decade}|[,\s]*)*$|'\
f'^\s*({prior_decades}|{current_decade})(\s*:\s*{prior_decades}|\s*:\s*{current_decade}|\s*)?$'
问题陈述：
What I'd like to implement in century_set(), if possible, is the ability to use a regular expression to verify if a range is valid or not.
换一种说法：
“ 2018：2020” >>有效“ 2020：2018” >>无效
