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

https://pasteboard.co/bdtnVlEUocwy.png

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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