正则表达式需求：仅匹配指定中间两位数字的ID格式

Got it, let's sort out that regex issue for you. The core problem with your current pattern is how you're trying to match the middle -XX- segment—using square brackets [] here is wrong because they define a character set, not a set of full two-digit combinations. That's why it's matching any random two digits instead of your allowed values.

Let's Break Down the Fix #

First, let's recap your requirements:

• ID format: XXXXXX-XX-XXXX (6 digits, hyphen, specific two-digit code, hyphen, 4 digits)
• Allowed middle codes: 01, 02, 21, 22, 23, 24

Option 1: Simplified Regex (If You Don't Need Strict 6-Digit Validation) #

If the first 6 digits can be any numbers (no specific range rules), this clean pattern will work perfectly:

^\d{6}-(01|02|21|22|23|24)-\d{4}$

• ^\d{6}: Matches exactly 6 leading digits
• (01|02|21|22|23|24): Uses parentheses to group your allowed two-digit codes (the | means "or", so it only matches these exact combinations)
• -\d{4}$: Matches the final hyphen plus 4 digits, anchored to the end of the string to prevent extra characters.

Option 2: Preserving Your Original 6-Digit Validation Rules #

If you need to keep the strict rules for the first 6 digits (from your original regex: first two any digits, next two are 01-09 or 10-12, last two are 01-09, 10-29, or 30-31), we'll fix just the middle segment and simplify the redundant parts of your original pattern:

^[0-9]{2}(0[1-9]|1[0-2])(0[1-9]|[12][0-9]|3[01])-(01|02|21|22|23|24)-[0-9]{4}$

• I cleaned up redundant syntax like [0-0]{1} → 0 and [1-1]{1} → 1 to make the regex easier to read
• Replaced the broken [01|21|23|24|01]{2} with the correct grouped (01|02|21|22|23|24) to enforce your allowed middle codes.

Test Cases #

✅ Matches valid IDs:

• 880101-01-5332
• 121231-24-1234
• 990929-02-4321

❌ Rejects invalid IDs:

• 880101-03-5332 (middle code 03 not allowed)
• 880101-11-5332 (middle code 11 not allowed)
• 88010-01-5332 (only 5 leading digits)

内容的提问来源于stack exchange，提问作者SKL