LPM: variable comparison not working

[Rich Bowen]

Tom Braun wrote:
> 
> Ok, I'm trying to do some simple input data checking on a script I'm
> writing.  $book is a string entered from the keyboard.  @books is a list of
> available books.  Both are chomped, so no new lines should be present.  I'm
> doing something like this:
> 
> $valid = 0;
> foreach (@books) {
>         if ($_ eq $book) {
>                 $valid = 1;
>                 last;
> }
> }
> 
> This never matches, even when $book is a value in @books.  In trying to
> figure out why, I added a print statement to it as shown:
> 
> $valid = 0;
> foreach (@books) {
>         if ($_ eq $book) {
>                 $valid = 1;
>                 last;
> }
> print "$valid-$book-$_-\n";
> }
> 
> I get output like the following (I used dashes since none of the variables
> should have them):
> 
> --galatians-galatians
> --galatians-ephesians
> --galatians-philippians
> ...
> 0-galatians-philemon-
> 
> As if this is not interesting enough, I tried it on my Windows 95 box
> (running ActivePerl 5.6) and it worked fine (I'm writing and was testing it
> on Linux).  However, my linux box gives the same results from both Perl
> 5.005 and Perl 5.6.
> 
> Does anyone have any idea what is going on?  I've been beating my head
> against this for a couple days and just am not seeing it.  Thanks

If what you're trying to do is figure out if $string is contained in
@array, perhaps what you need to do is use a hash. (Yes, this is a
cop-out. I don't see what's wrong with your existing code, but it sure
looks like you have some extra \n's in there somewhere.)

chomp (@books, $book);
%contains = map {$_ => 1} @books;
print "It's in there!\n" if $contains{$book};

Rich
-- 
Director of Web Application Development  -  The Creative Group
                                 http://www.cre8tivegroup.com/
Author - Apache Server Unleashed - http://apacheunleashed.com/