求能匹配含未知值(uu)特定日期格式的正则表达式

Alright, let's break down what you need here: you want a regex that matches dates where either:

• It's a fully valid calendar date (like 12/12/2018),
• The month is uu but day/year are valid (like uu/12/2018),
• Both month and day are uu but year is valid (like uu/uu/2018),
• All parts are uu (like uu/uu/uu)

But it should reject dates where:

• Day is uu but month is valid (e.g., 12/uu/2018),
• Day and year are uu but month is valid (e.g., 12/uu/uu),
• Year is uu but month/day are valid (e.g., 12/12/uu)

Here's the adjusted regex based on Ofir Luzon's original valid date pattern, modified to include the uu placeholder rules:

^(?:uu/uu/uu)$|^(?:uu/uu/(?:(?:1[6-9]|[2-9]\d)?\d{2}))$|^(?:uu/(?:(?:31\/(?:0?[13578]|1[02]))|(?:(?:29|30)\/(?:0?[13-9]|1[0-2]))|(?:(?:0?[1-9]|1\d|2[0-8])\/(?:0?[1-9]|1[0-2])))(?:(?:1[6-9]|[2-9]\d)?\d{2}))$|^(?:(?:31\/(?:0?[13578]|1[02]))|(?:(?:29|30)\/(?:0?[13-9]|1[0-2]))|(?:29\/0?2\/(?:(?:(?:1[6-9]|[2-9]\d)?(?:0[48]|[2468][048]|[13579][26])|(?:(?:16|[2468][048]|[3579][26])00))))|(?:(?:0?[1-9]|1\d|2[0-8])\/(?:0?[1-9]|1[0-2]))\/(?:(?:1[6-9]|[2-9]\d)?\d{2}))$

Let's break down each section of this regex: #

• ^(?:uu/uu/uu)$: Matches the fully placeholder date uu/uu/uu
• ^(?:uu/uu/(?:(?:1[6-9]|[2-9]\d)?\d{2}))$: Matches dates where month and day are uu, and the year is a valid 4-digit (or 2-digit for modern eras) year
• ^(?:uu/(?:(?:31\/(?:0?[13578]|1[02]))|(?:(?:29|30)\/(?:0?[13-9]|1[0-2]))|(?:(?:0?[1-9]|1\d|2[0-8])\/(?:0?[1-9]|1[0-2])))(?:(?:1[6-9]|[2-9]\d)?\d{2}))$: Matches dates where month is uu, and the day/year form a valid calendar date (includes checks for 31-day months, 30-day months, and valid day ranges)
• The final segment is the adjusted version of Ofir Luzon's original valid date regex (limited to / as the separator), which matches fully valid calendar dates like 12/12/2018

Notes: #

• This regex uses / as the date separator (matching your examples). If you need to support - or . as well, you can replace each \/ with (?:\/|-|\.) (like in the original regex), but your examples all use / so this is focused on that.
• The year validation supports 2-digit years (e.g., 23 for 2023) and 4-digit years starting from 1600, which aligns with the original regex's behavior.

内容的提问来源于stack exchange，提问作者aggicd