Javascript Challenges - Count Repeating Letters

Javascript Challenges - Count Repeating Letters

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[bruslaw]

Thanks for this challenge idea. I came up with a somewhat different solution (before I watched yours), which also works when letters are mixed up:

function countLetters(str)
{
let obj = {};
str.split("").forEach(l => obj[l] ? obj[l]++ : obj[l] = 1);
return Object.entries(obj).reduce((total, entry) => total + entry[1] + entry[0], "");
}

[bulatbaltin]

Thanks a lot! Awesome as ever! Another simple approach
function countLetters(str) {
str += "#";
let letts = str[0];
let count = 0;
let result = "";
for (let char of str) {
if (letts === char) {
count++;
} else {
result += `${count}${letts}`;
letts = char;
count = 1;
}
}
return result;
}

[ayanbanerjee]

You are awesome!!!
I watch all your videos!!!
What you are doing..is actually helping a lot of new developers out there!!!
Lots of Love from India❤️❤️❤️
Please make more JavaScript challenges vieeos!! :)

[akhilsinghas]

What about the boundary case? When i = tempArray.length - 1
In that case comparing tempArray[i] with tempArray[i+1] will not give any error? Because index i+1 does not exist.
instead if condition should be if(temp[i] === temp[i+1] && i! = tempArray.length)

[yamilzavala]

Thanks for the challenges list..
For this specific case, i resolved this in this way:

function onlyLetters(str) {
let onlyLettersStr =

let objStr = onlyLettersStr.reduce((acc, curr) => {
acc[curr] = acc[curr] ? acc[curr] + 1 : 1
return acc
}, {})

let result = '';
for(let key in objStr) {
result += `${objStr[key]}${key}`
}
return result
}

[letoan]

it is count repeat of the next. not really repeat of whole string.

[kadirit]

I enjoyed the explanation, wanted to ask how u could use this function to count duplicate numbers, then return the most frequent number?

[codingbox]

Hi John, I love to watch your work. this is my approach for the following challenge. I found a bug in your approach is that if we so the result would be "4f1e2f1e2r3t2o" but using my approach the answer is "6f2e2r3t2o"

function countLetters(str) {
const givenArr = str.split("");
const uniqueArr = [...new Set(str)];

let letters = []

for (let i = 0; i < uniqueArr.length; i++) {
let count = 0;
for (let j = 0; j < givenArr.length; j++) {
if (uniqueArr[i] === givenArr[j]) {
count++;
}
}
let value = `${count}${uniqueArr[i]}`;
letters= [...letters, value];
}

return letters;
}

[m.talalmalick]

Thanks for the video. Can you please tell me which extension do you use for output console in the editor?

[anastely]

Thank you,
but why you don't use ES6+?

[senderiandocaminos]

Nicely done, please, count repeating numbers challenges in an array

[ProfessorLinux]

What if the letters are mixed ex: aabbnaajkkaa, since you are just comparing it to the next value?

[richardgomez]

where can I find challenges like this on yb or an another place mainly complex challenges?

[anouarelmaaroufi]

Thank you for your efforts, I came up with a solution that doesn't require space and it works well.

function countLetters(str) {
let start = 0;
let track = 0;
let count = 0;
let result = "";

while (track <= str.length) {
if (str[track] === str[start]) {
count += 1;
track++;
} else {
result += `${count}${str[start]}`;
start = track;
count = 0;
}
}

return result;
}

[dgknca]

What is your extension showing console output?

[cdu]

This is nice and all, but only if the letters are next to one another.

[singhvimlesh]

Can Anyone one help me out "Joan Smith" or "Matthew Joan Smith" how I will get only first and last word from these string.Answer must be : - for "Joan Smith" it will be (JS) and for "Matthew Joan Smith" it will be (MS).

[sajidahmad]

Line num 13 little confusing can anyone make it clear??

[murshidhaniffa]

This will only work if the letters are in order

[abdelkarimabouzi]

const countLetters = (str) => {
let letters = [...new Set(str)];
let vals = str.split("");
let result = "";
const counter = (arr, lett) => {
let count = 0;
arr.map(obj => {
if (obj === lett) {
count++
};
});
result += (count + lett);
};
letters.map(lett => counter(vals, lett));
return result;
};