在JavaScript中替換陣列中的重復值

 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");

這就是我的代碼的樣子，對于最后一個函式呼叫guessLetter("X")，我希望輸出類似于：

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

然而，它最終是：

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

我注意到字母“X”的副本沒有被替換，但我該如何解決這個問題？太感謝了！

uj5u.com熱心網友回復：

您的問題：

當您嘗試查找"X"from的索引時lettersOfTheWord，它將始終回傳2in 的第一次"X"出現lettersOfTheWord

解決您的問題。

Array.prototype.indexOf()接受fromIndex作為可選引數。您可以將執行的索參考作fromIndex.

你的固定小提琴

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");

更好的解決方案

您可以guessedLetters使用Array.map. For loop isirrelavent，你可以使用Array.indexOf它自己并且可以檢查找到的索引是否大于-1，這意味著元素存在于陣列中。

作業小提琴

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");

uj5u.com熱心網友回復：

我稍微簡化了你的代碼。

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

function guessLetter(letter){
    lettersOfTheWord.forEach((_letter,i)=>{
        if (letter===_letter && guessedLetters[i]==='_'){
            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");

問題在于您if應該添加&& guessedLetters[i]==='_'到您的代碼中。然后洗掉let index=lettersOfTheWord.indexOf(letter);然后替換i而不是index

此外，您可以使用for ... in回圈。使用中斷并跳過不必要的檢查

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

function guessLetter(letter){
    for(const i in lettersOfTheWord){
        if (letter===lettersOfTheWord[i] && guessedLetters[i]==='_'){
            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");

尖端：

• 你可以洗掉功能 generateUnderScore
• 了解更多關于 ES6 map & forEach
• 您不需要為您的let. 只是創建function name(..) {...}我認為，這更清晰

標籤：javascript 数组

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