Replace duplicate value in a an array in JavaScript

Question

let lettersOfTheWord =["W",'H','A','T','E','V','E','R'];
let guessedLetters = lettersOfTheWord.map(()=>'_');
var count=0;
function guessLetter(letter){
    for(let i=0; i<lettersOfTheWord.length;i++){
        if (letter===lettersOfTheWord[i] && guessedLetters[i]==='_'){
            guessedLetters[i]=letter;
            console.log("You entered:" + letter);
            console.log(`The current guessed letters: ${guessedLetters.toString()}`);
            console.log("Congradulations! You found a new letter.");
            count++;
            console.log(count);
        }
        if (letter!==lettersOfTheWord[i] && guessedLetters[i]!=='_'){
            console.log("wrong letter");
        }
    }
    if (count===lettersOfTheWord.length){
        console.log("you win");
    }
}
   

guessLetter("W");
guessLetter("H");
guessLetter("A");
guessLetter("T");
guessLetter("E");
guessLetter("H");
guessLetter("E");
guessLetter("R");

So I have changed my code now. The new problem is what if I would like to print out the "wrong letter" information if the call function has a wrong argument?

 let lettersOfTheWord =['F','O','X',"X"];
 let guessedLetters = [];
 let generateUnderScore = function(word){
    for (let i =0; i<word.length; i++){
        guessedLetters.push("_");
    }
    //console.log(guessedLetters.toString());
    return guessedLetters;
} //to generate underscore.
generateUnderScore(lettersOfTheWord);
 let guessLetter =function(letter){
     for (let i=0; i<lettersOfTheWord.length;i++){
         if (letter===lettersOfTheWord[i]){
             let index=lettersOfTheWord.indexOf(letter);
             guessedLetters[index]=letter;
             console.log(guessedLetters);
    
         }
     }
     console.log("You entered:" + letter);
     console.log(`The current guessed letters: ${guessedLetters.toString()}`);
     console.log("Congradulations! You found a new letter.")

     
    }
 

  guessLetter("F");
  guessLetter("O");
  guessLetter("X");
  guessLetter("X");

This is what my code looks like, for the last function call guessLetter("X"), I would like the output to be something like:

You entered:X
The current guessed letters: F,O,X,X
Congratulations! You found a new letter.

However, it ends up with:

You entered:X
The current guessed letters: F,O,X,_
Congratulations! You found a new letter.

I noticed the duplicate of letter "X" was not replaced, but how do I fix this problem? Thank you so much!

Do not use an array. Use a Map instead.

ceving
– ceving

2021-12-15 11:01:52 +00:00
Commented Dec 15, 2021 at 11:01 — ceving
– ceving, Commented Dec 15, 2021 at 11:01

kstepien · Accepted Answer · 2021-12-16 09:30:03Z

1

I little bit of simplified your code.

const UNKNOWN_LETTER = '_';
let lettersOfTheWord =['F','O','X',"X"];
let guessedLetters = lettersOfTheWord.map(() => UNKNOWN_LETTER);

function guessLetter(letter){
    lettersOfTheWord.forEach((_letter,i)=>{
        if (letter===_letter && guessedLetters[i] === UNKNOWN_LETTER) {
            guessedLetters[i]=letter;
            console.log(guessedLetters);
            console.log("You entered:" + letter);
            console.log(`The current guessed letters: ${guessedLetters.toString()}`);
            console.log("Congradulations! You found a new letter.")
        }
    });
}

guessLetter("F");
guessLetter("O");
guessLetter("X");
guessLetter("X");

The problem was in your if you should add && guessedLetters[i]==='_' to your code. And remove let index=lettersOfTheWord.indexOf(letter); then replace i instead of index

Also, you can use the for ... in loop. To use the break and skip unnecessary checks

const UNKNOWN_LETTER = '_';
let lettersOfTheWord =['F','O','X',"X"];
let guessedLetters = lettersOfTheWord.map(() => UNKNOWN_LETTER);

function guessLetter(letter){
    for(const i in lettersOfTheWord){
        if (letter===lettersOfTheWord[i] && guessedLetters[i]===UNKNOWN_LETTER) {
            guessedLetters[i]=letter;
            console.log(guessedLetters);
            console.log("You entered:" + letter);
            console.log(`The current guessed letters: ${guessedLetters.toString()}`);
            console.log("Congradulations! You found a new letter.");
            break;
        }
    }
}

guessLetter("F");
guessLetter("O");
guessLetter("X");
guessLetter("X");

TIPS:

you can remove function generateUnderScore
learn more about ES6 map & forEach
you don't need to provide function to your let. Just create function name(..) {...} I think, this is more clerable

edited Dec 16, 2021 at 9:30

answered Dec 15, 2021 at 11:15

kstepien

1,23111 silver badges19 bronze badges

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

4 Comments

Alexzhang Over a year ago

what does this do ? ()=>'_'

kstepien Over a year ago

the map function creates a new array with the same length like lettersOfTheWord but, sets for the each keys the "_" value , so you will receive a ["_", "_", "_", "_"]

Alexzhang Over a year ago

i have a new question regarding the code, could you please look into it for me?

kstepien Over a year ago

what is that question?

Nitheesh · Accepted Answer · 2021-12-15 11:48:23Z

Your Issue:

When you try to find the index of "X" from lettersOfTheWord, it will always return 2 which is the fist occrance of "X" in lettersOfTheWord

Fix to your problem.

Array.prototype.indexOf() accepts fromIndex as an optional parameter. You can use the index of the execution as the fromIndex.

Your Fixed Fiddle

let lettersOfTheWord = ['F', 'O', 'X', "X"];
let guessedLetters = [];
let executionIndex = 0;
let generateUnderScore = function (word) {
  for (let i = 0; i < word.length; i++) {
    guessedLetters.push("_");
  }
  //console.log(guessedLetters.toString());
  return guessedLetters;
} //to generate underscore.
generateUnderScore(lettersOfTheWord);
let guessLetter = function (letter) {
  for (let i = 0; i < lettersOfTheWord.length; i++) {
    if (letter === lettersOfTheWord[i]) {
      let index = lettersOfTheWord.indexOf(letter, executionIndex);
      guessedLetters[index] = letter;
      // console.log(guessedLetters);
    }
  }
  console.log("You entered:" + letter);
  console.log(`The current guessed letters: ${guessedLetters.toString()}`);
  console.log("Congradulations! You found a new letter.");
  executionIndex++;
}
guessLetter("F");
guessLetter("O");
guessLetter("X");
guessLetter("X");

Better Solution

You can rewrite guessedLetters using Array.map. For loop isirrelavent, you can use Array.indexOf itself and can check whether the found index is greater that -1, which means element exist in array.

Working Fiddle

let lettersOfTheWord = ['F', 'O', 'X', "X"];
let guessedLetters = lettersOfTheWord.map(item => '_');
let executionIndex = 0;

let guessLetter = function (letter) {
  const index = lettersOfTheWord.indexOf(letter, executionIndex);
  index > -1 ? guessedLetters[index] = letter : {};
  console.log("You entered:" + letter);
  console.log(`The current guessed letters: ${guessedLetters.toString()}`);
  console.log("Congradulations! You found a new letter.");
  executionIndex++;
}
guessLetter("F");
guessLetter("O");
guessLetter("X");
guessLetter("X");

there is a problem if you guess letters in that way -> F, X, O, X

Collectives™ on Stack Overflow

Replace duplicate value in a an array in JavaScript

2 Answers 2

4 Comments

1 Comment

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

4 Comments

1 Comment

Your Answer

Sign up or log in

Post as a guest

Related