How do i replace a specific element in a JavaScript array without knowing the index?-CodePudding

hi ive looked at similar questions but they weren't helpful.

I am creating a guestlist that takes 10 people, if the user tries to add an 11th name to the array, the program should say, “You have already added 10 people to your guest list. Would you like to replace someone on the list with this person? y/n: ”

If the user enters “y”, the program should output the current guest list and then asks, “Who would you like to replace?”

this is my code:


let i = 0;
let input = names;
do {
   
   input = names.push(prompt("Who would you like to invite to your dinner party?"));

 i  ;
}
while (names.length < 11);

if (names.length == 11 ){
   input2 = prompt(`You have already added 10 people to your guest list. Would you like to
   replace someone on the list with this person? Y/N:`)
}

let yes = "Y";
let no = "N";

if (input2 === yes){
   replaceInput = prompt((`Your guests are:${names}
  
  Who would you like to replace?`));
} 

alert(`your new guests are: ${names}`)

now how do i make the program replace the person the user specifies with the 11th person given and output the updated list?

CodePudding user response：

you can directly use push() method in javascript arrays. For example:

<html>
<body>

<h1>JavaScript Arrays</h1>
<h2>The push() Method</h2>

<p>push() adds new items to the end of an array:</p>

<p id="demo"></p>

<script>
const fruits = ["1", "2", "3", "4"];
fruits.push("5", "6");

document.getElementById("demo").innerHTML = fruits;
</script>

</body>
</html>

when you run this code the result will be:

1,2,3,4,5,6

CodePudding user response：

Find the index of selected guest and replace the guest on that index with the 11th guest. Check the example code for more clarification:

// inputs
let currentNames = ["X1", "X2", "X3", "X4", "X5", "X6", "X7", "X8", "X9", "X10"]

// this variable will have the result of the first prompt() call (new guest)
let newName = "X11";

// this variable will have the result of the second prompt() call (guest to replace the new guest with)
let nameToReplace = "X5";

// implementation
let indexOfNameToReplace = currentNames.indexOf(nameToReplace);
if (indexOfNameToReplace > -1) {
  currentNames[indexOfNameToReplace] = newName;
  console.log(`New array is: ${currentNames}`);
  // New array is: [X1,X2,X3,X4,X11,X6,X7,X8,X9,X10]
} else {
  console.log(`No guest found by the given name: "${nameToReplace}"`)
}

CodePudding user response：

let names = [];
let i = 0;
let input = names;
do {
  input = names.push(
    prompt("Who would you like to invite to your dinner party?")
  );

  i  ;
} while (names.length < 11);

if (names.length == 11) {
  input2 = prompt(`You have already added 10 people to your guest list. Would you like to
   replace someone on the list with this person? Y/N:`);
}

let yes = "Y";
let no = "N";

if (input2 === yes) {
  replaceInput = prompt(`Your guests are:${names}
  
  Who would you like to replace?`);
  newInput = prompt("Enter New guest name: ");

  const nameReplace = names.indexOf(replaceInput);

  if (nameReplace !== -1) {
    names[nameReplace] = newInput;
  }
}

alert(`your new guests are: ${names}`);