> -----Original Message-----
> From: John W. Krahn [mailto:[EMAIL PROTECTED]]
> Subject: Re: "Use of uninitialized value" error message
>
> Jason Larson wrote:
> >
> > I'm still new to Perl myself, so I can't tell you exactly
> what's happening,
> > but it looks like $result_value1 is undef when it gets to
> the if statement.
> > I think a better way to accomplish what you're trying to do
> is simply:
> >
> > my $result_value1;
> > if ($result_value) { #$result_value1 is defined
> ^^^^^^^^^^^^^^^^^^ ^^^^^^^
> This is _NOT_ testing whether $result_value1 is defined or
> not (in fact
> it is not testing $result_value1 at all :-), it is testing whether
> $result_value1 is true or false which is not the same thing.
>
> if ( defined $result_value1 ) { #$result_value1 is defined
>
Doh! My bad... You are, of course, correct. Thanks for pointing out my
error.
(for any beginners reading this that may not understand the difference, let
me give a quick example...)
use warnings;
use strict;
my $result_value = "0";
if ($result_value) {
print "\$result_value is defined and is: $result_value";
} else {
print "\$result_value is undefined"
}
__END__
This prints out "$result_value is undefined", which is obviously not true.
If we change the if statement as John pointed out, we get a better result
if (defined $result_value) {
This prints out "$result_value is defined and is: 0", which is a better
evaluation of the variable.
Sorry about the confusion, and I hope this helps...
Jason
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