How can I change elements inside and array

Question

How can I get the "e" elements inside of "arr" to be replaced by change0 ?

The arr array will be an input by the user and I need to change it there is no way to predict which element will be "e" .

var arr = [ "a", "b", "c", "d", "e", "f", "g", "h", "e", "j", "e"];

var change0 = 2

var change1 = 1

document.write(arr);

Answer 1

You could use map() method and this will return new updated array and save original.

 var arr = [ "a", "b", "c", "d", "e", "f", "g", "h", "e", "j", "e"]; var change0 = 2; var result = arr.map(e => e == 'e' ? change0 : e); console.log(result) 

Answer 2

You can do this using join and split methods.

 var replace="change0"; var arr = [ "a", "b", "c", "d", "e", "f", "g", "h", "e", "j", "e"]; console.log(arr.join().split('e').join(replace).split(',')); 

Answer 3

Run a loop for getting index of element "e" and then repeat until there are more elements left:

 var arr = [ "a", "b", "c", "d", "e", "f", "g", "h", "e", "j", "e"]; while (arr.indexOf("e") > 0){ var index = arr.indexOf("e"); arr[index] = "change0"; } document.write(arr); 

Answer 4

You could use Array#indexOf and search for all elements and change then with the given value.

 var array = [ "a", "b", "c", "d", "e", "f", "g", "h", "e", "j", "e"], search = "e", change = 2, p = array.indexOf(search); while (p !== -1) { array[p] = change; p = array.indexOf(search, p + 1); } console.log(array); 

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Answer 5

You can use indexOf to determine the index of the element in an array. So basically, you can just go like this:

arr[arr.indexOf('e')] = change0;

It will not work if you have multiple element that have the values of 'e'. It will only change the first one so you have to put it through a loop. Or use map.

Answer 6

Using forEach :

 var arr = [ "a", "b", "c", "d", "e", "f", "g", "h", "e", "j", "e"]; var change = "changed"; arr.forEach(function(v, i) { if(v === "e") arr[i] = change; }); console.log(arr); 

Answer 7

1. Convert to string
2. Replace 'e'
3. Convert back to array

 var arr = [ "a", "b", "c", "d", "e", "f", "g", "h", "e", "j", "e"]; console.log((((arr.toString()).replace(/e/g,"changed"))).split(',')); 

Answer 8

If you intend to handle more than one letter, it's best to prepare encoder/decoder (a function or an array) in advance. Then your job becomes as simple as:

output = input.map(val => encoder[val] || val);

The || val || val part is for values not handled by the encoder.

Working example

In this example, we use split("") to convert string to array and join("") to do the opposite.

 PrepareCodec: var Latin = "abcdefghijklmnoprstuvyzABCDEFGHIJKLMNOPRSTUVYZ"; var Cyrillic = "абцдефгхийклмнопрстувызАБЦДЕФГХИЙКЛМНОПРСТУВЫЗ"; var encoder = {}, decoder = {}; for (let i in Latin) encoder[Latin[i]] = Cyrillic[i]; for (let i in Cyrillic) decoder[Cyrillic[i]] = Latin[i]; EncryptionTest: var src = prompt("Enter text to encrypt:", "Hello, world!"); var enc = src.split("").map(val => encoder[val] || val).join(""); DecryptionTest: enc = prompt("Enter text to decrypt:", enc); var dec = enc.split("").map(val => decoder[val] || val).join(""); FinalResult: prompt("Decrypted text:", dec);