Unable to capitalize the word in JS

Question

I am trying to change the entire word into capital letters. What is wrong with my approach, for individual letters toUpperCase is working fine

var name = "gates";
for (var i=0; i< name.length; i++){
name[i] = name[i].toUpperCase();
}
name;

So the thing is "hello world".toUpperCase() is working fine as expected. Why the looping individual characters in array does not work as expected!. Is this some property in arrays/strings especially in JS?

As RGraham mentioned the string letters cannot be modified, I don't understand the negative feedback of the community. Even the question seems to be valid.

use toUpperCase function, Please google before post it on stackoverflow — Arunprasanth K V, Jun 11 '15 at 12:23
May be I asked the question wrongly, I will update my question — gates, Jun 11 '15 at 12:25
possible duplicate of [Capitalize words in string](http://stackoverflow.com/questions/2332811/capitalize-words-in-string) — suvroc, Jun 11 '15 at 12:26
Possible duplicate of [string.charAt(x) or string\[x\]?](http://stackoverflow.com/questions/5943726/string-charatx-or-stringx). Seriously! — Álvaro González, Jun 11 '15 at 12:28
Im trying to help, and just curius why you want to do it like this. Dont be mad brah — The_Monster, Jun 11 '15 at 12:32
You can edit the question but you are negative towards the people that are trying to help. — The_Monster, Jun 11 '15 at 12:33
I am exploring the JS , so "hello world".toUpperCase() worked fine, but done with a loop did not. So got curious and asked. @The_Monster — gates, Jun 11 '15 at 12:34

score 4 · Accepted Answer · answered Jun 11 '15 at 12:25

4

The reason this doesn't work, is that accessing a string using the array syntax is read-only. As per the MDN docs:

For character access using bracket notation, attempting to delete or assign a value to these properties will not succeed. The properties involved are neither writable nor configurable. (See Object.defineProperty() for more information.)

So, console.log(name[0]) will work, but name[0] = "G"; will not update the name variable.

answered Jun 11 '15 at 12:25

CodingIntrigue

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This is the answer I am looking for! – gates Jun 11 '15 at 12:29
@gates You're welcome. Don't be discouraged by the voting and comments on your question. It read absolutely fine to me. – CodingIntrigue Jun 11 '15 at 12:30
I must appologize I must have overread the paragraph directly following the code. Revoced my downvote. – bwright Jun 11 '15 at 12:44

score 2 · Answer 2 · answered Jun 11 '15 at 12:23

2

You don't need to loop through the letters, just do:

var name = "gates";
name = name.toUpperCase();

answered Jun 11 '15 at 12:23

Mathew Thompson

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score 2 · Answer 3 · answered Jun 11 '15 at 12:25

A string is immutable in most languages, meaning, you can't change individual characters, or add something, without ending up with a new one.

name = name.toUpperCase();

Will give you what you need, but a new, all-caps string is put in the variable 'name'.

score 1 · Answer 4 · answered Jun 11 '15 at 12:23

1

Accoring to http://www.w3schools.com/jsref/jsref_touppercase.asp

var str = "Hello World!";
var res = str.toUpperCase();

answered Jun 11 '15 at 12:23

bwright

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score 1 · Answer 5 · answered Jun 11 '15 at 12:23

1

http://www.w3schools.com/jsref/jsref_touppercase.asp

var str = "Hello World!";
var res = str.toUpperCase();

Result:

HELLO WORLD!

answered Jun 11 '15 at 12:23

The_Monster

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Unable to capitalize the word in JS

5 Answers5