Question

I tested the following regexp for US prices (delimiter comma, separator dot) which is running fine:

 ^[1-9][0-9]{0,2}(?:,?[0-9]{3}){0,3}(\.[0-9]{2})?$

It works, prices like 30,000.000 are refused. Only 2 decimals are accepted.

I tried to exchange them for handling European prices:

^[1-9][0-9]{0,2}(?:.?[0-9]{3}){0,3}(\,[0-9]{2})?$

but it does not work, prices like 30.000,000 are accepted, which is wrong. Only 2 decimals should be accepted.

What’s wrong in these 2 regexps?

Answer 1

In regex, . is a special character so when you want to match a literal dot you need to escape it with a backslash (\.). This is not the case for commas, so you can leave them unchanged.

In your attempt you switched the , and the . which left you with an unescaped . and a \, at the end, when you actually want to switch the , and the \. like this:

^[1-9][0-9]{0,2}(?:\.?[0-9]{3}){0,3}(,[0-9]{2})?$