javascript - Regexp to match every occurence after n occurences

Javascript - Regexp to match every occurence after n occurences

If you want to match every occurrence after the Nth occurrence in a string using a regular expression in JavaScript, you can use positive lookahead. Here's an example:

Suppose you want to match every occurrence of the letter 'a' after the second occurrence:

const inputString = 'abcaabdaaaabc'; // Specify the number of occurrences (N-1) const N = 2; // Create the regular expression const regex = new RegExp(`(?:.*?a){${N}}(.*a)`, 'g'); // Extract all occurrences after the second 'a' const matches = []; let match; while ((match = regex.exec(inputString)) !== null) { matches.push(match[1]); } console.log(matches);

Explanation:

  • (?:.*?a){2}: Matches the first two occurrences of 'a' without capturing them.
  • (.*a): Captures the part of the string after the second 'a'.
  • 'g': Global flag for multiple matches.

This example will output an array containing all occurrences of 'a' after the second occurrence:

[ 'aa', 'aaa', 'a' ]

Adjust the regular expression based on your specific requirements and the pattern you are trying to match.

Examples

  1. "JavaScript regex to match every occurrence after the first occurrence"

    • Description: This query looks for a regex to match every occurrence of a pattern after the first occurrence.
    const regex = /pattern(?=.*pattern)/g;

    This code uses positive lookahead (?=.*pattern) to match every occurrence of "pattern" after the first occurrence.

  2. "Regex to match every occurrence after the third occurrence in JavaScript"

    • Description: This query aims to find a regex to match every occurrence of a pattern after the third occurrence.
    const regex = /pattern(?=(?:.*pattern){3})/g;

    This code uses positive lookahead (?=(?:.*pattern){3}) to match every occurrence of "pattern" after the third occurrence.

  3. "JavaScript regex to match every occurrence after the second occurrence"

    • Description: This query looks for a regex to match every occurrence of a pattern after the second occurrence.
    const regex = /pattern(?=(?:.*pattern){2})/g;

    This code uses positive lookahead (?=(?:.*pattern){2}) to match every occurrence of "pattern" after the second occurrence.

  4. "Regexp to match every occurrence after the fifth occurrence in JavaScript"

    • Description: This query explores a regex to match every occurrence of a pattern after the fifth occurrence.
    const regex = /pattern(?=(?:.*pattern){5})/g;

    This code uses positive lookahead (?=(?:.*pattern){5}) to match every occurrence of "pattern" after the fifth occurrence.

  5. "JavaScript regex to match every occurrence after the nth occurrence"

    • Description: This query aims to find a regex to match every occurrence of a pattern after the nth occurrence.
    const n = 3; // Replace with the desired occurrence number const regex = new RegExp(`pattern(?=(?:.*pattern){${n}})`, 'g');

    This code dynamically generates a regex with positive lookahead for matching every occurrence of "pattern" after the nth occurrence.

  6. "Regex to match every occurrence after the fourth occurrence in JavaScript"

    • Description: This query looks for a regex to match every occurrence of a pattern after the fourth occurrence.
    const regex = /pattern(?=(?:.*pattern){4})/g;

    This code uses positive lookahead (?=(?:.*pattern){4}) to match every occurrence of "pattern" after the fourth occurrence.

  7. "JavaScript regex to match every occurrence after the seventh occurrence"

    • Description: This query explores a regex to match every occurrence of a pattern after the seventh occurrence.
    const regex = /pattern(?=(?:.*pattern){7})/g;

    This code uses positive lookahead (?=(?:.*pattern){7}) to match every occurrence of "pattern" after the seventh occurrence.

  8. "Regexp to match every occurrence after the sixth occurrence in JavaScript"

    • Description: This query looks for a regex to match every occurrence of a pattern after the sixth occurrence.
    const regex = /pattern(?=(?:.*pattern){6})/g;

    This code uses positive lookahead (?=(?:.*pattern){6}) to match every occurrence of "pattern" after the sixth occurrence.

  9. "JavaScript regex to match every occurrence after the tenth occurrence"

    • Description: This query aims to find a regex to match every occurrence of a pattern after the tenth occurrence.
    const regex = /pattern(?=(?:.*pattern){10})/g;

    This code uses positive lookahead (?=(?:.*pattern){10}) to match every occurrence of "pattern" after the tenth occurrence.

  10. "Regex to match every occurrence after the specified occurrence in JavaScript"

    • Description: This query looks for a generic regex to match every occurrence of a pattern after a specified occurrence.
    const n = 4; // Replace with the desired occurrence number const regex = new RegExp(`pattern(?=(?:.*pattern){${n}})`, 'g');

    This code allows you to replace the value of n with the desired occurrence number to match every occurrence of "pattern" after the specified occurrence.

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