How to loop a string or convert a string to an array in JS? Or find a better solution to solve this

Question

I am at hour 14 of learning JavaScript, and doing some challenges.

The aim of this code is to find out how often a numbr occurs in the input.

The output is correct, if it occurs once it needs to be 0. (Don't ask me why this is?! They want it like that and might have a reason. )

I don't think the solution is the most elegant. You can surely help me out here and tell me how to write it better. I had to add " " to the first and last position of the input and then - to convert it into an array - remove them again or it would create a new empty item to the array ( i think). Is there a better way to accomplish this?

var input =" 12 34 56 78 12 34 1 87 12 "
var digits= input.trim();
    digits= digits.split(" ");
var arrayLength= digits.length;
var output ="";

for(var n=0; n<arrayLength; ++n){
    var outputD =-1;  
    var inputLocal = input;

    while (inputLocal.search(" " + digits[n] +" ") >= 0) {
        inputLocal = inputLocal.replace(" " +digits[n]+" ", ""); 
        ++outputD;
    } 
output += " " + outputD;
console.log(output);
};

CD.. · Accepted Answer · 2015-05-17 17:58:02Z

1

You can use a object as a map for counting, then use map to create the new array and then use join, like:

var input = ' 12 34 56 78 12 34 1 87 12 '
    arr = input.trim().split(' '),
    count = {}, result;

arr.forEach(function(item){
  if (typeof count[item] !== 'undefined') {
    count[item]++;
  } else {
    count[item] = 0; 
  }
});

result = arr.map(function(item){
  return count[item];
});

console.log(result.join(' '));

answered May 17, 2015 at 17:58

CD..

74.4k25 gold badges160 silver badges170 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

Peter Seliger · Accepted Answer · 2015-05-17 21:31:12Z

1

console.log(
  " 12 34 56 78 12 34 1 87 12 "

  .trim()
  .split(/\s+/)

  .reduce(function (collector, item) {

    if (item in collector) {
      ++collector[item]
    } else {
      collector[item] = 0; // 1
    }
    return collector;

  }, {})
);

answered May 17, 2015 at 21:31

Peter Seliger

13.5k3 gold badges31 silver badges45 bronze badges

Collectives™ on Stack Overflow

How to loop a string or convert a string to an array in JS? Or find a better solution to solve this

2 Answers 2

Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related