[RESOLVED] Match exact number of uppercase letters

[TecBrat]

I want to match 5 uppercase letters followed by a dash, followed by 5 more uppercase letters. I tested this:

<script type="text/javascript">
var str="^This is a test. PIYRW-NKJDQ"; 
var patt1=/[A-Z]{5}-[A-Z]{5}/g;
document.write(str.match(patt1));
</script>

and if I change the last part of str to "XXPIYRWV-XNKJDQ" it matches
"IYRWV-XNKJD" when I want it to return null. What am I doing wrong?

[MikeOS]

var str="^This is a test. PIYRW-NKJDQ"; 
var patt1=/[A-Z]{5}-[A-Z]{5}$/g;
document.write(str.match(patt1));

Note the bold $ symbol, this indicates that the match much occur at the end of the string. If you try it now it will work fine.

[clueful]

Presumably you want the match not to be preceded by an uppercase letter.

Perhaps:

/(^|[^A-Z])[A-Z]{5}-[A-Z]{5}/g

[TecBrat]

Note the bold $ symbol, this indicates that the match much occur at the end of the string. If you try it now it will work fine.

Thanks for the reply.
Take a look here:

<script type="text/javascript">
var str="This is a test. PIYRW-NKJDQ but it doesn't do what I want"; 
var patt1=/[A-Z]{5}-[A-Z]{5}$/g;
document.write(str.match(patt1));

var str1="This is a test. PIYRWXX-NKJDQYY but it doesn't do what I want"; 
var patt1=/[A-Z]{5}-[A-Z]{5}$/g;
document.write(str.match(patt1));

I'd like the first one to return PIYRW-NKJDQ, but the second one to return null.

maybe it would help if I explained what I want to do.
I am trying to recognize an item number in a search string. If someoone searches for "HAPPY-HOLIDAYS", it would match "HAPPY-HOLID" incorrectly) If they type "ABCDE-FDSAA yellow" I'd like the item number to still be recognized.

[thraddash]

Try this expression:

/(^| )([A-Z]{5}-[A-Z]{5})( |$)/

That will check that the words you are looking for are either at the beginning of the sentence, at the end, or standing alone with at least 1 space on either side.
I did these examples to make sure it worked:

var str = "This is a test. PIYRW-NKJDQ but it doesn't do what I want";
document.write(
	($match = str.match(/(^| )([A-Z]{5}-[A-Z]{5})( |$)/)) === null ? 'NO MATCHES FOUND' : $match[2]
);

document.write('<br />');

var str = "This is a test. PIYRWXX-NKJDQYY but it doesn't do what I want";
document.write(
	($match = str.match(/(^| )([A-Z]{5}-[A-Z]{5})( |$)/)) === null ? 'NO MATCHES FOUND' : $match[2]
);

[TecBrat]

Thanks:

Let's see if I read this right

/(^| )([A-Z]{5}-[A-Z]{5})( |$)/

first match is begin or space, second match is capital letters {exactly 5}, hyphen, capital letters {exactly 5}, third match is space or end.

Then we use the second match.

Is that right?
I might understand this stuff after all!

For my own reference, the next time I look up this thread:
http://www.w3schools.com/jsref/jsref_obj_regexp.asp

[TecBrat]

I am far from a wiz, but thanks to the couple of answers you've given me, I am well on my way to writing my own expressions.

Thanks again.