How to check date format if it have different input like 'yyyy-mm-dd' or 'yyyymmdd'?

Question

i have question how to check date input?

Here's some algorithm that i make

#The input
Enter the date: yyyy-mm-dd #The format is string
or
Enter the date: yyyymmdd


if the input like yyyy-mm-dd:
   print(yyyy-mm-dd)
else if the input like yyyymmdd:
   print(yyyy-mm-dd)
else: #If the input have alphabet
   print ("Sorry, wrong format bro!")

Is it possible?

Answer 1

This ensures a valid date format goes through. The regex solution will allow in stuff like 2020-99-99.

import datetime

date = "2020-02-01"

def format_check(date, fmt):
    try: datetime.datetime.strptime(date, fmt)
    except: return False
    else: return True
    
if not format_check(date, '%Y-%m-%d') and not format_check(date, '%Y%m%d'):
    raise ValueError("Sorry, wrong format bro!")

Answer 2

您可以使用像 re'\\d{4}-\\d{2}-\\d{2}' 这样的正则表达式，在这里我们需要正好 4 个数字，2 个数字，然后是另外 2 个代表天和月的数字，然后是 4 个数字代表年份