如何在“/”之前和之后生成最多 3 个数字字符的正则表达式，其中“/”之前的数字应该大于“/”之后的数字

Question

I have to generate a regex with following conditions

• Max of 3 numeric chars before and after the "/" Max of 7 chars
• including "/" and no other special chars & decimals allowed
• Numbers before the "/" should be greater than numbers after the "/"

I have tried this so far

^\d{3}(\/\d{3})?$

How will I fix this validation on regex "Numbers before the "/" should be greater than numbers after the "/""?

Can anyone please help me out?

Answer 1

You won't be able to achieve this with a regular expression alone (at least, not that easily or readably) - instead, capture both digit parts, and check that the first digits are greater than the second:

 const check = str => { const match = str.match(/^(\\d{1,3})\\/(\\d{1,3})$/); if (!match) { return false; } const [, d1, d2] = match; return Number(d1) > Number(d2); }; console.log( check('123/456'), check('456/123'), check('45/123'), check('12/45') );

Answer 2

You can assign two variables - One for the digits before '/' and one for after. like A/B, then use split() function with '-' as the delimiter and then compare the two parts with >.

As far as I know, numeric values cannot be compared in Regex.