RegEx for matching digits and failing on special chars

Question

My regex below matches everything with this 千 character after the digits. I want to be able to match only if 千 is present but not if it is followed by 伏 or 吨

\(\d{1,}(?:\,?\d{3})*(?:\.\d+)?[ ]?)(!千伏|!千吨|千)\

Currently:

220千伏 (match '220千')
220千吨 (match '220千')
220千 (match '220千')

Expected:

220千伏 (no match)
220千吨 (no match)
220千 (match '220千')

Answer 1

My guess is that you may want to have a list to exclude certain things and have other specific chars, maybe something similar to:

\d{1,}(?:\,?\d{3})*(?!千伏|千吨)(?:千)

RegEx

You can design/modify/change your expressions in regex101.com.

RegEx Circuit

You can visualize your expressions in jex.im:

JavaScript Test

const regex = /\d{1,}(?:\,?\d{3})*(?!千伏|千吨)(?:千)/gm;
const str = `220千伏
220千吨
220千`;
let m;

while ((m = regex.exec(str)) !== null) {
    // This is necessary to avoid infinite loops with zero-width matches
    if (m.index === regex.lastIndex) {
        regex.lastIndex++;
    }
    
    // The result can be accessed through the `m`-variable.
    m.forEach((match, groupIndex) => {
        console.log(`Found match, group ${groupIndex}: ${match}`);
    });
}

Also, you might not want to escape non-metachars, just like Barmar advised, which you could modify this part of your expression:

\d{1,}(?:\,?\d{3})*