Angular2 Typescript how to increment alphabet index

Question

I know how to do this in Php, as it is a simple, but i am struggling to get a version working.

for ($i = 'A'; $i < 'Z'; $i++) {                   
    $k = $i;
    $k++;
    echo "$i->$k, ";
}

Basically i want to pass a letter into a function and get the next letter in the alphabet. Is there any easy ways or directions that i could be pointed in.

Possible duplicate of [Convert integer into its character equivalent in Javascript](http://stackoverflow.com/questions/3145030/convert-integer-into-its-character-equivalent-in-javascript) — vusan, Dec 22 '16 at 07:08

score 1 · Accepted Answer · answered Aug 02 '16 at 09:04

1

This should do what you want:

getNextLetter(char: String): String {
    code: Number = char.charCodeAt(0);
    code++;
    return String.fromCharCode(code);
}

answered Aug 02 '16 at 09:04

Maximilian Riegler

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ahh perfect just what i was trying to achieve! thanks – Jezyk Danzowki Aug 02 '16 at 09:12

score 1 · Answer 2 · answered Aug 02 '16 at 09:15

Here is a working code for you:

https://plnkr.co/edit/SP6LzMfLzeNniiteDmRQ?p=preview

var upper = [ 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z' ];
var alphabet = {};

for(var j = 0; j < upper.length; j++)
  alphabet[upper[j]] = j;

console.log(alphabet);

function NextLetter(l)
{
  console.log('Current letter index:', alphabet[l]);
  console.log('Next letter:',upper[alphabet[l]+1] );
}

//Test 
NextLetter('C');

score 0 · Answer 3 · answered Aug 02 '16 at 09:03

There are two nice JS functions that can help you out:

charCodeAt - extracts the letter Unicode.

fromCharCode - parse Unicode to a letter.

var k, i = 'A'.charCodeAt();
var loopEnd = 'Z'.charCodeAt();

for (i; i < loopEnd; i++) {                   
    k = i;
    k++;
    console.log(String.fromCharCode(i) + " -> " + String.fromCharCode(k));
}

score 0 · Answer 4 · answered Jul 22 '20 at 15:33

I had a similar issue, I modified the answer to this and it worked for me... from the fronted inside for loop just call getNextLetter(i);

typescript code:

 getNextLetter(num): String {
     var code: number = "abcdefghijklmnopqrstuvwxyz".charCodeAt(num);
     return String.fromCharCode(code); 
 }

Angular2 Typescript how to increment alphabet index

4 Answers4