How can I tally the frequency of characters in a given string using Javascript and output them as numerical values?

Question

How can I tally the frequency of characters in a given string using Javascript and output them as numerical values?

I am in the process of tallying the frequency of each individual character within a given string and representing them as numbers.

For example, let's consider the string "HelloWorld".

HELLOWORLD There is one H - so 1 should be displayed with H removed.

ELLOWORLD There is one E - so 1 should be displayed and E removed.

LLOWORLD There are three L - so 3 should be displayed and all L characters removed.

OWORD There are two O - so 2 should be displayed and all O characters removed.

WRD There is only one occurrence of each character - so simply display 1 1 1.

In the end, I would like to concatenate all the numbers to get the result:

1132111 (this can be represented as either a string or a number).

Would it be possible to achieve this?

Thank you for taking the time to read this, any tips or advice would be greatly appreciated!

javascript string count numbers

Answer 1

Answer №1

Give this approach a shot using basic while loops

function characterCount(str){
str = str.split('');
        //this will be the result
let finalResult = ''
let count = 1;
while(str.length !== 0){
count = 1;
                //check for duplicates of a letter in str
while(str.indexOf(str[0]) !== str.lastIndexOf(str[0])){
count++;
                        //delete the last instance of the duplicate
str.splice(str.lastIndexOf(str[0]),1)
}
                //once all duplicates of first letter are removed, remove the first letter from str
str.shift();
finalResult += count; 
}
return finalResult;
}
console.log(characterCount("helloarena"));

Answer 2

Give this approach a shot using basic while loops

function characterCount(str){
str = str.split('');
        //this will be the result
let finalResult = ''
let count = 1;
while(str.length !== 0){
count = 1;
                //check for duplicates of a letter in str
while(str.indexOf(str[0]) !== str.lastIndexOf(str[0])){
count++;
                        //delete the last instance of the duplicate
str.splice(str.lastIndexOf(str[0]),1)
}
                //once all duplicates of first letter are removed, remove the first letter from str
str.shift();
finalResult += count; 
}
return finalResult;
}
console.log(characterCount("helloarena"));

Answer 3

Answer №2

Discover a more efficient method using reduce

function countOccurrences(str) {
  str = str.split('');

  var occurrences = str.reduce((acc, char) => {
    acc[char] = ++acc[char] || 1;
    return acc
  }, {})

  return Object.values(occurrences).join('')
}

console.log(countOccurrences('helloworld'))

Answer 4

Discover a more efficient method using reduce

function countOccurrences(str) {
  str = str.split('');

  var occurrences = str.reduce((acc, char) => {
    acc[char] = ++acc[char] || 1;
    return acc
  }, {})

  return Object.values(occurrences).join('')
}

console.log(countOccurrences('helloworld'))

How can I tally the frequency of characters in a given string using Javascript and output them as numerical values?

Answer №1

Answer №2

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