JavaScript: Replace the first digit in a string (should contains at least digit) with $ character

Last update on February 24 2025 12:01:52 (UTC/GMT +8 hours)

JavaScript Basic: Exercise-136 with Solution

Replace First Digit in String with $

Write a JavaScript program to replace the first digit in a string (should have at least one digit) with the $ character.

Visual Presentation:

JavaScript: Replace the first digit in a string (should contains at least digit) with $ character.

Sample Solution:

JavaScript Code:

/**
 * Function to replace the first digit in a string with '$'
 * @param {string} input_str - The input string
 * @returns {string} - The modified string with the first digit replaced by '$'
 */
function replace_first_digit(input_str) {
  // Using regular expression to replace the first occurrence of a digit with '$'
  return input_str.replace(/[0-9]/, '$');
}

console.log(replace_first_digit("abc1dabc")); // Output: "abc$dabc"
console.log(replace_first_digit("p3ython")); // Output: "p$ython"
console.log(replace_first_digit("ab1cabc")); // Output: "ab$cabc"

Output:

abc$dabc
p$ython
ab$cabc

Live Demo:

Flowchart:

ES6 Version:

/**
 * Function to replace the first digit in a string with '$'
 * @param {string} input_str - The input string
 * @returns {string} - The modified string with the first digit replaced by '$'
 */
const replace_first_digit = (input_str) => {
  // Using regular expression to replace the first occurrence of a digit with '$'
  return input_str.replace(/[0-9]/, '$');
};
console.log(replace_first_digit("abc1dabc")); // Output: "abc$dabc"
console.log(replace_first_digit("p3ython")); // Output: "p$ython"
console.log(replace_first_digit("ab1cabc")); // Output: "ab$cabc"

For more Practice: Solve these Related Problems:

Write a JavaScript program that locates the first digit in a string and replaces it with the '$' character, preserving the remaining characters.
Write a JavaScript function that searches for the first occurrence of a numerical digit in a string and substitutes it with a dollar sign.
Write a JavaScript program that scans a string for its first digit and replaces that digit with '$', ensuring the string contains at least one digit.

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