RegExp Match Doesnt Contain Words

RegEx to tell if a string does not contain a specific character

Are you trying to test whether or not a string does not contain a character using regular expressions ?
Are you trying:

• Use Regex to enable the widest range of validations, and
• Always look for a positive match (i.e. instead of using !Regex.IsMatch(cell, regexvariable), I wanted to rely on always being able to use Regex.IsMatch(cell, regexvariable) since the majority of DataTables invoking this method will be using the positive match instead of the negative.

Solution

I came across this question looking for the same thing but for JavaScript. The expression above did not work in my case, but I came across the below expression which did:

RegExp

^((?!0).)*$

RegExp Explanation

• Match whole strings except 0 (zero)

Other example

i want to find and match a string from all local javascript file import statement without .js extension:

RegExp

^import.*\/((?!.js).)*([\'\"]);$

RegExp Modern Approach

^import.*\/((?!.js).)*(['"]);$

String to match

import notranslate from '../translator/notranslate.js';
import notranslate from '../translator/notranslate'; // <-- i want match this

RegExp Explanation

• ^ asserts position at start of a line
• import matches the characters import literally (case sensitive)
• ((?!.js).)* 1st Capturing Group
• • * matches the previous token between zero and unlimited times, as many times as possible, giving back as needed (greedy)

  A repeated capturing group will only capture the last iteration. Put a capturing group around the repeated group to capture all iterations or use a non-capturing group instead if you’re not interested in the data

• • / matches the character / with literally (case sensitive)
• (?!.js) Negative Lookahead

  Assert that the Regex below does not match

• • . matches any character (except for line terminators)
• • js matches the characters js literally (case sensitive)
• . matches any character (except for line terminators)
• ([\'\"]) 2nd Capturing Group
• • [\'\"] Match a single character present in the list below
• • \' matches the character ' with literally (case sensitive)
• • \" matches the character " with literally (case sensitive)
• ; matches the character ; with literally (case sensitive)
• $ asserts position at the end of a line

Global pattern flags

• g modifier: global. All matches (don’t return after first match)
• m modifier: multi line. Causes ^ and $ to match the begin/end of each line (not only begin/end of string)

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