remove n occurrences of exclamation marks in a string javascript

user_4756106 0
Viewed 1016

I am wondering if anyone knows how to replace n number of occurrences of exclamation marks in a string. I need to remove n exclamation marks in the sentence from left to right and n is always positive integer.

An example would be as follows:

remove("Hi!!!",1) === "Hi!!"
remove("!!!Hi !!hi!!! !hi",3) === "Hi !!hi!!! !hi"

I have tried many approaches but have had no luck so far. Here is my latest attempt.

function remove(str, n){
   str.replace(/!{n}/g, '');
}
ecmascript-6 javascript
3 Answers

You can use the replacer function in .replace() to replace only the first number of items upto the passed value of num:

const remove = function(str, n) {
  let i = 0;
  const res = str.replace(/!/g, match => i++ < n ? '' : match); // if i is smaller than the num, replace it with nothing (ie remove it) else, when i becomes greater, leave the current matched item in the string and don't remove it
  return res;
}

console.log(remove("Hi!!!", 1)); // === "Hi!!"
console.log(remove("!!!Hi !!hi!!! !hi", 3)) // === "Hi !!hi!!! !hi"

Or, if you like, a one-liner:

const remove = (str, n) => str.replace(/!/g, match => n --> 0 ? '' : match); 

// Results: 
console.log(remove("Hi!!!", 1)); // === "Hi!!"
console.log(remove("!!!Hi !!hi!!! !hi", 3)) // === "Hi !!hi!!! !hi"

user_56489540

Idea: Match/replace all exclamation marks, but check n in the replacement function and conditionally return either an empty string (remove !) or the original string (keep !).

Also, decrement n each time a ! is replaced by nothing.

function remove(str, n) {
    return str.replace(/!/g, function (m0) {
        if (n > 0) {
            n--;
            return '';
        }
        return m0;
    });
}

console.log(remove("Hi!!!",1));
console.log(remove("!!!Hi !!hi!!! !hi",3));

This algorithm removes all exclamation marks if n is higher than the number of ! in the input string.

user_18486540

You could take the count as counter and check ich it reaches zero. if not decrement and replace with an empty string, otherwise replace with the found string.

const remove = (s, n) => s.replace(/\!/g, _ => n && n-- ? '' : _);

console.log(remove("Hi!!!", 1) === "Hi!!");
console.log(remove("!!!Hi !!hi!!! !hi", 3) === "Hi !!hi!!! !hi");

user_14476750
Related