There are a couple of errors in your code:

1. if($thing2 =~ /\s*<$thing\s*>/)

   For your examples this line equates to

   if( 'abcd<Utly>' =~ /\s*<Ut\s*>/)
   [download]

   There is no way that \s* will ever match 'ly'.

2. $thing2 =~ s/$thing/$thing/;

   Even if the match was made, this line is saying: Look in 'abcd<Utly>' for 'Ut' and if you find it replace 'Ut' with 'Ut', which probably isn't what you want:)

If your arrays are of any size, your nested loops comparing every element of one array with every element of the second is going to take a quite a long while to run...if they're small then that probably doesn't matter, but you could make the process more efficient by using a hash, but it's probably better to get this one working before you move on.

Ugh. You can use @1 and @2 if you are masochistic, but please don't make us read code like that. It's hideous.

That said, I think you are trying to do this:

my @abbrs   = qw( Ut ); 
my @strings = qw( abcd<Utly> );
for $abbr ( @abbrs ) { 
    for $str ( @strings ) { 
        $str =~ s/<$abbr(.*)>/<$abbr>/; 
    }
}
[download]

-sauoq
"My two cents aren't worth a dime.";

That's all good advice, but I'd make some corrections / improvements to your regexp.

One thing that you should be doing is using \Q and \E in your replacement. That is, you want to be replacing a literal abbreviation, not an abreviation-pattern. Also, you should limit that ".*". Granted, ".*?" would be good enough for most people, but I prefer to be explicit. Additionally, there is no reason to catch the latter half of the word being abreviated (so, drop the parenthesese). Last of all, you probably want to perform this replacement as many times as it occurs, so add a /g modifier:

    $str =~ s/<\Q$abbr\E[^>]*>/<$abbr­>/g;
[download]


------------
:Wq
Not an editor command: Wq

That's all good advice, but I'd make some corrections / improvements to your regexp.

Well, I wouldn't go so far as to call any of that a "correction."

You offer at least one improvement, however. There's certainly no reason to capture as I was. Using [^>]* is arguably better as well, although it wouldn't be likely to make much of a practical difference in this case.

As for your other changes, while I am a firm believer in robust and explicit regular expressions, I also believe strongly in keeping things simple. Given my understanding of the OP's question, I'd guess that both your \Q quoting and the /g modifier are probably unnecessary. (In fact, my decision not to use /g and my decision not to use non-greedy matching went hand in hand.)

My sense of the problem after reading the explanation and the code was that each string had only one such replacement. (Perhaps I should've suggested a last; in there as well.) After reading it again, I can see where that might be an incorrect assumption. I may have given too much weight to the single example he gave.

Still, keeping the regex relatively close to the OP's original attempt might help his understanding, and that, afterall, was my real intent.

++ for your rigor though and I do appreciate the feedback.

-sauoq
"My two cents aren't worth a dime.";