How to extract the last N digits from a number in TypeScript

1 Answer

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/*
    Extracts the last N digits from a given number.

    Approach:
      - To get the last N digits, compute: number % (10 ** digits)
      - This avoids string manipulation and uses efficient arithmetic.

    Parameters:
      number : the original integer
      digits : how many digits to extract from the end

    Returns:
      The last N digits as a number.
*/
function getLastNDigits(num: number, digits: number): number {
    // Compute 10^digits using the exponent operator (**)
    const divisor: number = 10 ** digits;

    // Modulo returns the remainder, which is exactly the last N digits
    return num % divisor;
}

// Example values
const num: number = 987654321;
const digits: number = 4;

// Extract the last N digits
const result: number = getLastNDigits(num, digits);

// Display the result
console.log("Original number:", num);
console.log("Digits requested:", digits);
console.log("Last " + digits + " digits:", result);


/*
run:

Original number: 987654321
Digits requested: 4
Last 4 digits: 4321

*/

 



answered Sep 18 by avibootz
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