Modifying the index value within an array

Question

Modifying the index value within an array

I am facing a challenge where I must remove a letter from each element in an array and alter the first letter if it is at index 0. My current strategy involves the following code:

function capital(arr, char){
    let str = "";
    let result = "";
for (let i = 0; i < arr.length; i++){
    str = arr[i] + (i < arr.length - 1 ? ",": "");;

    for (let j = 0; j < str.length; j++){
        if (str[j] === char){
            result += "";
             if (str[j] === char){
            result += (j === 0? "A": "");
        }
        
        else {
            result += str[j];
        }
    }
}
    console.log(result);
}
capital(["doritos","sandking","bandana", "demand"], "d");

This program aims to eliminate all instances of the letter 'd' in the strings and change the first letter to 'A' if 'd' is at index 0.

The current output is

Aoritos,sanking,banana,Aeman

However, the desired result should be

Aritos,sanking,banana,Aman

The condition is that built-in functions cannot be used, and the program needs to be case insensitive. I can work on addressing these concerns by tweaking the code and adding conditional statements, but I need help specifically with ensuring the modification to index 0. Any assistance would be greatly appreciated. Thank you!

javascript arrays function conditional-statements

Answer 1

Answer №1

To determine if the character in your input is located at the beginning of a string, you can use str.indexOf(char). If it is found at the first index, add the prefix "A" to the string without the first character using str.substring(1).

function capitalizeFirst(arr, char) {
  let str = "";
  let result = "";
  for (let i = 0; i < arr.length; i++) {
    str = arr[i];
    if(str.indexOf(char) === 0) {
      result = 'A' + str.substring(1);
    } else {
      result = str;
    }

    console.log(result);
  }
}
capitalizeFirst(["doritos", "sandking", "bandana", "demand"], "d");

Answer 2

To determine if the character in your input is located at the beginning of a string, you can use str.indexOf(char). If it is found at the first index, add the prefix "A" to the string without the first character using str.substring(1).

function capitalizeFirst(arr, char) {
  let str = "";
  let result = "";
  for (let i = 0; i < arr.length; i++) {
    str = arr[i];
    if(str.indexOf(char) === 0) {
      result = 'A' + str.substring(1);
    } else {
      result = str;
    }

    console.log(result);
  }
}
capitalizeFirst(["doritos", "sandking", "bandana", "demand"], "d");

Answer 3

Answer №2

Consider this approach

function replaceFirstLetter(arr, char) {

  return arr.map(e => {

    let isFirst = false;
    if (e[0] == "d") isFirst = true;
    e = e.replace(new RegExp(char, 'ig'), '');
    if (isFirst)
      e = e.replace(e.charAt(0), "A");
    return e;
  });

}
console.log(replaceFirstLetter(["doritos", "sandking", "bandana", "demand"], 'd'))

Answer 4

Consider this approach

function replaceFirstLetter(arr, char) {

  return arr.map(e => {

    let isFirst = false;
    if (e[0] == "d") isFirst = true;
    e = e.replace(new RegExp(char, 'ig'), '');
    if (isFirst)
      e = e.replace(e.charAt(0), "A");
    return e;
  });

}
console.log(replaceFirstLetter(["doritos", "sandking", "bandana", "demand"], 'd'))

Answer 5

Answer №3

To update the first letter of a word when it matches a passed letter at index 0, iterate through each letter and add non-matching letters to the result.

const capitalize = ch => {
 const letter = ch.charCodeAt(0);
 if(letter >= 97 && letter <= 122) {
    return String.fromCharCode(letter - 32);
 }
 return ch;
}

const capital = (words, ch) => {
  let result = '';
  for(let i = 0; i < words.length; i++) {
    let newWord = '';
    for(let j = 0; j < words[i].length; j++) {
      if(capitalize(words[i][j]) === capitalize(ch) && j === 0) {
        newWord = 'A';
      }
      if(capitalize(words[i][j]) !== capitalize(ch)) {
        newWord += words[i][j];
      }
    }
    result += newWord;
    if(i < words.length - 1 ) {
      result += ',';
    }
  }
  return result;
}

const result = capital(["doritos","sandking","bandana", "demand", "sandDking"], "d");
console.log(result);

Answer 6

To update the first letter of a word when it matches a passed letter at index 0, iterate through each letter and add non-matching letters to the result.

const capitalize = ch => {
 const letter = ch.charCodeAt(0);
 if(letter >= 97 && letter <= 122) {
    return String.fromCharCode(letter - 32);
 }
 return ch;
}

const capital = (words, ch) => {
  let result = '';
  for(let i = 0; i < words.length; i++) {
    let newWord = '';
    for(let j = 0; j < words[i].length; j++) {
      if(capitalize(words[i][j]) === capitalize(ch) && j === 0) {
        newWord = 'A';
      }
      if(capitalize(words[i][j]) !== capitalize(ch)) {
        newWord += words[i][j];
      }
    }
    result += newWord;
    if(i < words.length - 1 ) {
      result += ',';
    }
  }
  return result;
}

const result = capital(["doritos","sandking","bandana", "demand", "sandDking"], "d");
console.log(result);

Modifying the index value within an array

Answer №1

Answer №2

Answer №3

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