Removing everything except capital letters using replace

Question

Yeah, I'm trying to remove everything except the capital letters, though it doesn't really seem to go well.

I used the following code,

String.replace(/(?![A-Z])./, '');

It doesn't seem to work properly, while it does work using PHP.

Note: PHP and JavaScript have different flavors of regex, both of which are expansions on the [formal definition of regex](https://en.wikipedia.org/wiki/Regular_expression), so it isn't necessarily a safe assumption that one language's regex will transfer to another... not to say that this example isn't an overlap between the two — Patrick Barr, Aug 02 '17 at 15:55

score 6 · Accepted Answer · answered Aug 02 '17 at 15:50

6

Add the global option at the end of the regex - see demo below:

console.log("AkjkljKK".replace(/(?![A-Z])./g, ''));

answered Aug 02 '17 at 15:50

kukkuz

If you don't use `global` option, only the first character match will be replaced... – kukkuz Aug 02 '17 at 15:54
That explained it, does it work the same way in PHP too? I barely every used replacements in strings. – Martijn Ebbens Aug 02 '17 at 16:02
I'm not aware with how PHP does it, but more or less every language handles it in the same way - with some slight changes in syntax... – kukkuz Aug 02 '17 at 16:03
1

Thanks for the quick help! (: – Martijn Ebbens Aug 02 '17 at 16:08

Dij · Answer 2 · 2017-08-02T15:57:36.523

4

you can use [^A-Z] to remove everything except capital letters. Also use g to replace all occurrences and not just the first one.

var str = "sOmeVALUE";

console.log(str.replace(/[^A-Z]/g, ""));

edited Aug 02 '17 at 15:57

answered Aug 02 '17 at 15:51

Dij

2 Answers2